Acquisition and Transfer of Territorial Sovereignty
(p. 215) 9 Acquisition and Transfer of Territorial Sovereignty1
1. Introduction
Disputes concerning title to land territory, including islands, and over the precise determination of boundaries are regularly the subject of international proceedings. Recourse to arbitration may be part of an overall peace settlement.2 But many such conflicts are dormant and it is only when a dispute flares up that it receives publicity. While the occupation of territory not belonging to any state (terra nullius) is no longer a live issue, issues concerning such occupation in the past may still arise. Legally relevant events may have occurred centuries ago.3 The pressures of national sentiment, the exploitation of areas once thought barren or inaccessible, the strategic significance of areas previously neglected, and the pressure of population on resources suggest that territorial disputes will continue to be significant.
References(p. 216) 2. Determining Title
(A) The Centrality of Title4
If the basic unit of the international legal system is the state, the space which the state occupies in the world is its territory, traditionally thought of as realty, with the state (a person) its proprietor. Thus there were sales and bequests of state territory, leaseholds and reversions, with little or no regard for the wishes of the inhabitants. Indeed international law developed a notion of entitlement to territory well before the state itself developed as a normative concept. Thereafter title arose not simply by physical occupation (i.e. actual administration, often referred to as effectivités) but through acquisition in accordance with law—although until 1928, the law included the rule that coerced treaties were valid.5 Yet there were areas of uncertainty, with territory (oft en islands, islets, or rocks but sometimes whole provinces) contested between states.6 In such cases it was largely a historical question which of the claimant states had the better claim.
Where the act corresponds exactly to law, where effective administration is additional to the uti possidetis iuris, the only role of effectivité is to confirm the exercise of the right derived from a legal title. Where the act does not correspond to the law, where the territory which is the subject of the dispute is effectively administered by a State other than the one possessing the legal title, preference should be given to the holder of the title. In the event that the effectivité does not co-exist with any legal title, it must invariably be taken into consideration. Finally, there are cases where the legal title is not capable of showing exactly the territorial expanse to which it relates. The effectivité can then play an essential role in showing how the title is interpreted in practice.7
Thus title prevails over possession, but if title is equivocal, possession under claim of right matters.
Title to territory, like ownership of land, is normally ‘objective’, but there is no system of registration, no international Torrens title.8 Unquestioned title is a contingencyReferences(p. 217) arising from history, general recognition, and the absence of any other claimant. Title may be relative in several quite different contexts.
(1) The principle nemo dat quod non habet(no donor can give a greater interest than he or she already has) places a restrictive effect on titles dependent on bilateral agreement: see chapter 8.
(2) A judicial decision on issues of title cannot foreclose the rights of third parties.
(3) In a situation where physical holding is not conclusive of the question of right, recognition becomes important, and this may be forthcoming from some states and not others.
(4) The compromison the basis of which a dispute is submitted to a court or tribunal may assume that title is to go to one of the two claimants. In Minquiers and Ecrehos the Court interpreted the compromisas excluding a finding that the islets were res nulliusor subject to a condominium.9In such a case, in the absence of any other claimant, the result seems to be a title valid against all, but the parties have not had to come up to any minimum requirements of effective control.
(5) In any event, in instances such as Island of Palmas and Minquiers and Ecrehos,10the Court assesses the relative intensity of the competing acts of state authority to determine which party has the better right.
(6) In appropriate circumstances the Court will lean in favour of title in one claimant even though there are grounds for a finding that the territory was at the relevant time terra nullius. Thus in Eastern Greenland11Danish activity in the disputed area had hardly been intensive, but the Court refused to consider the area terra nullius.12
(7) In some cases the sheer ambiguity of the facts may lead the Court to rely on matters which are less than fundamental,13or to seek evidence of acquiescence by one party. In this context it is academic to use the classification ‘inchoate’. A title, though resting on very preliminary acts, is sufficient as against those without a better title.14In coming to a decision on the question of right, it may be necessary to measure ‘titles’ against each other.15
References(p. 218) (B) The Intertemporal Law16
In many instances the rights of parties to a dispute derive from a legally significant act done, or treaty concluded, long ago. As Fitzmaurice says, it is ‘an established principle of international law that in such cases the situation in question must be appraised, and the treaty interpreted, in the light of the rules of international law as they existed at the time, and not as they exist today’.17 In Island of Palmas, Judge Huber stated the principle and continued: ‘The effect of discovery by Spain is…to be determined by the rules of international law in force in the first half of the 16th century—or (to take the earliest date) in the first quarter of it…’.18 The rule has also been applied in the interpretation of treaties concerning territory.19 It is justified by reference to the need for predictability and stability in the international system of title.20
As regards the question which of different legal systems prevailing at successive periods is to be applied in a particular case (the so-called intertemporal law), a distinction must be made between the creation of rights and the existence of rights. The same principle which subjects the act creative of a right to the law in force at the time the right arises, demands that the existence of the right, in other words its continued manifestation, shall follow the conditions required by the evolution of law.21
This extension of the doctrine has been criticized on the grounds that to require title to be actively maintained at every moment of time would threaten many titles and lead to instability.22 This emphasizes the need for care in applying the rule.23 In any case the intertemporal principle does not operate in a vacuum: its impact will be reducedReferences(p. 219) by the effect of recognition, acquiescence, and the rule that abandonment is not to be presumed. Thus in Pedra Branca, the historic title of the Sultanate of Johore to the disputed features survived into the modern period, despite little or nothing by way of the exercise of governmental authority over them.24
(C) The Critical Date25
In any dispute a certain date will assume prominence in the process of evaluating the facts. The choice of such a date is within the province of the tribunal and will depend on the logic of the law applicable to the facts as well as on the practical necessity of confining the dossier to the more relevant facts and thus to acts prior to the existence of a dispute. In the latter context the tribunal is simply excluding evidence consisting of self-serving acts of parties after the dispute arose. But evidence of acts and statements occurring after the critical date may be admissible if not self-serving, as in the case of admissions against interest. There are several types of critical date, and it is difficult and probably misleading to formulate general definitions:26 the facts of the case are dominant (including the terms of the special agreement empowering the tribunal to hear the case) and there may be no necessity for a tribunal to choose any date whatsoever.
In some cases there will be several dates of significance. Eastern Greenland arose from a Norwegian proclamation of 10 July 1931 announcing occupation of the area. The Court held that ‘as the critical date is July 10th, 1931…it is sufficient [for Denmark] to establish a valid title in the period immediately preceding the occupation.’27 In Island of Palmas the US claimed as successor to Spain under a treaty of 10 December 1898, and everything turned on the nature of Spanish rights at that time. The Court did not specifically choose a critical date in Minquiers and Ecrehos.28 In Argentine-Chile Frontier the tribunal ‘considered the notion of the critical date to be of little value in the present litigation and…examined all the evidence submitted to it, irrespective of the date of the acts to which such evidence relates’.29
References(p. 220) (D) Terra Nullius30
Terra nullius is land not under the sovereignty or authority of any state; occupatio was the mode by which such territory could be acquired.31 In the modern context, it has fallen into disuse. This is because there remains on the surface of the earth no truly ‘vacant’ territory,32 but also because the term gradually assumed imperialist overtones when it was used to justify colonization of large areas of inhabited lands through a theory of European supremacy. That theory underlay the Congress of Berlin of 1885 but now ‘stands condemned’.33 In Western Sahara, the Court had to decide whether the Western Sahara was terra nullius at the time of Spanish colonization (in the 1890s). It held it was not, because the people of the territory were socially and politically organized under chiefs with a capacity to represent them. In fact the territory was acquired by treaty, not occupation.34
3. The ‘Modes’ of Acquisition
(A) Basic Principles
Standard textbooks, particularly those in English, classify the modes of acquisition in a stereotyped way reflecting those of Roman law.35 According to this analysis there are five modes of acquisition—occupation, accretion, cession, conquest, and prescription. But the concept of modes of acquisition is unsound in principle: such labels only make the task of analysis more difficult.36 The inadequacies of the orthodox approach are more apparent when the relevant questions have been examined, but a few things may be usefully said here.
First, it is common to classify the five orthodox modes of acquisition as ‘original’ or ‘derivative’. Occupation and accretion are usually described as ‘original’, cession as ‘derivative’. There are differences of opinion in regard to conquest and prescription, and again the classification has no practical value.37 In one sense all titles are original, since much depends on the acts of the grantee in the case of a cession. In any event theReferences(p. 221) dual classification oversimplifies the situation, and the modes described as ‘derivative’ are so in rather different ways. Moreover the usual analyses do not explain how title is acquired when a new state comes into existence.38 Events leading to independence of the new state are mostly within the domestic jurisdiction of another state, yet they are legally relevant to territorial disputes involving the new state. In this type of case there is no ‘root of title’ as such: title is a by-product of the events leading to the creation of a state as a new source of territorial sovereignty.39
Secondly, in determining title, a tribunal will concern itself with proof of the exercise of sovereignty via conduct à titre de souverain before the critical date or dates, and will not apply the orthodox analysis to describe its process of decision. The issue of territorial sovereignty is often complex and involves the application of various legal principles to the facts, including (as concerns the modern period) principles deriving from the prohibition on the acquisition of territory by force and the invalidity of coerced treaties. The result often cannot be ascribed to any single ‘mode of acquisition’. Orthodox analysis does not allow for the interaction of acquiescence and recognition with the other rules. Furthermore, a category like ‘cession’ or ‘prescription’ may bring quite distinct situations into unhappy fellowship.40 Lastly, the importance of showing a better right in contentious cases, that is, of relative title, is obscured if too much credit is given to the five ‘modes’. Thus the following headings represent categories of convenience.
(B) Original and Historic Title
It may happen that a current dispute involves not only reliance upon the exercise of state authority but the invocation of an ancient, original or historic title. The concept informs the principle of ‘immemorial possession’ and reliance upon evidence of general repute or opinion as to matters of historical fact. Particularly in Asia, traditional boundaries play a significant role.41 International tribunals have recognized the concept of ancient or original title,42 but require appropriate evidence in support.
(C) Effective Occupation43
The concept of effective occupation in international law represents the type of legal relation which in private law would be described as possession. In Eastern GreenlandReferences(p. 222) the Permanent Court said ‘a claim to sovereignty based not upon some particular act or title such as a treaty of cession but merely upon continued display of authority, involves two elements each of which must be shown to exist: the intention and will to act as sovereign, and some actual exercise or display of such authority’.44 This statement has not lost its force, and was (in part) reiterated in Eritrea/Yemen: ‘[t]he modern international law of the acquisition (or attribution) of territory generally requires that there be: an intentional display of power and authority over the territory, by the exercise of jurisdiction or State functions, on a continuous and peaceful basis’.45
In the absence of a formal basis of title in a treaty or judgment, and in a system without registration of title, possession plays a significant role. It must be borne in mind that ‘legal possession’ involves a search for an interest worth protection by the law. Legal policy may lead a court to regard as sufficient a tenuous connection with the territory in certain conditions. Moreover, what is important is state activity and especially acts of administration: use by local peoples generally lacks this element and is only tangentially relevant.46‘Occupation’ here derives from occupatio in Roman law and does not necessarily signify occupation in the sense of actual settlement and a physical holding.
As in private law, the concept of effective occupation is complex, and many difficulties arise in applying it to the facts. Precisely what acts will be sufficient to found sovereignty is a matter of fact and degree,47 and may depend on the character of the territory: for example, the bar with respect to remote and sparsely settled areas will be set lower than in the context of more heavily populated territory.
Effective and long-established occupation is key to a claim of acquisitive prescription, although courts and tribunals have rarely applied that doctrine as such.48 In practice it may not be easy to distinguish effective occupation and prescription, and neither Island of Palmas nor Eastern Greenland employs the categories. Beckett classified the former as a case of prescription, the latter as resting on occupation.49 But in both cases the issue was simply which of two competing sovereignties had the better right. Prescription classically involves usurpation, yet these cases involved, for all practical purposes, contemporaneous, competing acts of state sovereignty. InReferences(p. 223) Minquiers and Ecrehos, the Court stated the issue as one of possession,50 which in the context was equated with sovereignty.51 Its task was ‘to appraise the relative strength of the opposing claims to sovereignty over the Ecrehos’.52
(i) Discovery53
This category, much employed, is equally unsatisfactory for the purpose of legal analysis. It links the concept of ‘discovery’ to that of terra nullius, and is discredited for the same reasons. At one time it was thought that in the fifteenth and sixteenth centuries discovery conferred a complete title.54 But it seems that it gave no more than an inchoate title: an effective act of appropriation seems to have been necessary.55 The modern view, certainly, is that it gave no more than an inchoate title, an option, as against other states, to proceed to effective occupation within a reasonable time.56 In Island of Palmas the US argued that, as successor to Spain, its title derived from Spanish discovery in the sixteenth century. Huber responded that, even if discovery without more gave title at that time, the continued existence of the right must be determined according to the law prevailing in 1898, the critical date. In his opinion the modern law is that ‘an inchoate title of discovery must be completed within a reasonable period by the effective occupation of the region claimed to be discovered’.57 British58 and Norwegian59 practice supports this view. The US view now is that mere discovery gives no title, inchoate or otherwise, and this has much to commend it.60 The notion of discovery only makes sense if it is placed firmly in the context of effective occupation, and it is best to avoid the category altogether. Further, the notion of inchoate title is misleading. Title is never ‘inchoate’, though it may be weak if it rests on slight evidence of state activity.
References(p. 224) (ii) Symbolic annexation61
Symbolic annexation62 may be defined as a declaration or other act of sovereignty or an act of private persons, duly authorized, or subsequently ratified by a state, intended to provide unequivocal evidence of the acquisition of sovereignty over a parcel of territory or an island. The subject must be seen as a part of the general question of effective occupation. There is no magic in the formal declaration of sovereignty by a government, whether or not this is preceded, accompanied or followed by a formal ceremony in the vicinity. In the case of uninhabited, inhospitable and remote regions little is required in the nature of state activity and a first, decisive act of sovereignty may suffice to create a valid title. But in principle the state activity must satisfy the normal requirements of ‘effective occupation’. ‘Symbolic annexation’ does not give title except in special circumstances (as in Clipperton Island). However, it is a part of the evidence of state activity. It has been stated that ‘a prior State act of formal annexation cannot after a long interval prevail against an actual and continuous display of sovereignty by another State’.63 But if the initial act was effective to vest title then a latecomer can only succeed, if at all, on the basis of prescription or acquiescence. To require too much in respect of the maintenance of rights may encourage threats to the peace. In the case of remote islands, it is unhelpful to require a determinate minimum of ‘effectiveness’, once title is actually established.64
if a territory, by virtue of the fact that it was completely uninhabited, is, from the first moment when the occupying State makes its appearance there, at the absolute and undisputed disposition of that State, from that moment the taking of possession must be considered as accomplished, and the occupation is thereby completed.65
References(p. 225) The annexation, though symbolic in form, had legal effect.
(iii) Effective and continuous display of state authority
As was noted by Huber in Island of Palmas ‘the actual continuous and peaceful display of state functions is in the case of dispute the sound and natural criterion of territorial sovereignty’.66 This is in contrast to older works on international law, stressing a nineteenth-century view of occupation in terms of settlement and close physical possession.67 Rather the question has become one of administrative character, under which those acts which are reflective of the intention to govern, and not merely to possess in some nominal fashion, are constitutive of title.68
Thus, in Island of Palmas the Dutch claim to the contested territory was preferred on the basis of evidence ‘which tends to show that there were unchallenged acts of peaceful display of Netherlands sovereignty from 1700 to 1906 and which…may be regarded as sufficiently proving the existence of Netherlands sovereignty’.69In Eastern Greenland the Danish claim, based not on any physical presence in the contested territory but on (a) the long-term presence of colonies in other parts of Greenland, (b) the wording of legislation and treaties so as to render them applicable to Eastern Greenland, and (c) seeking to have the resulting title recognized internationally, was held to be superior to the Norwegian claim, based on the wintering of various expeditions in the territory and the construction of a wireless station there. The Permanent Court held that Denmark, at least in the 10 years prior to Norwegian involvement, had ‘displayed and exercised her sovereign rights to an extent sufficient to constitute valid title to sovereignty’.70
The emphasis on the display of state activity, and the interpretation of the facts in the light of a legal policy which favours stability and allows for the special characteristics of uninhabited and remote territories, suggest a change in the law.71 The modern law concentrates on title, on evidence of sovereignty, and the notion of occupation has been refined accordingly.72 Thus in Minquiers and Ecrehos in relation to the Ecrehos group the Court was concerned with acts involving the exercise of jurisdiction, local administration, such as the holding of inquests,73 and a British Treasury Warrant of 1875 constituting Jersey a Port of the Channel Islands.74
References(p. 226) By contrast acts by private persons purporting to appropriate territory may be ratified by the state and may then constitute evidence of its effective occupation.75 Otherwise they will have no legal effect.76
(iv) The intention to act as sovereign
The requirement of an intention to act as sovereign, otherwise referred to as animus occupandi77 or animus possidendi,78 is generally stressed. However, the notion may create more problems than it solves: Ross described the subjective requirement of the ‘will to act as sovereign’ as ‘an empty phantom’.79 In truth the subjective criterion is unrealistic in seeking a coherent intention from activity involving numerous individuals often over a considerable period of time. Furthermore, the criterion begs the question in many cases where there are competing acts of sovereignty.80
In certain contexts, however, the animus occupandi (or something like it) has a function. First, the activity must be à titre de souverain in the sense that the agency must be that of the state and not of unauthorized persons. Secondly, it has a negative role: if the activity is by the consent of another state recognized as the rightful sovereign then no amount of state activity is capable of maturing into sovereignty. Thirdly, the state activity taken as a whole may be explicable only on the basis that sovereignty is assumed.81 Thus in Minquiers and Ecrehos the fact that both parties had conducted official hydrographic surveys of the area was not necessarily referable to an assertion of sovereignty by either. But certain forms of activity, whilst not necessarily connected with territorial sovereignty, have probative value, for example, the exercise of criminal jurisdiction.
(D) Cession82
A right to territory may be conferred by treaty, provided the transferee takes in accordance with the treaty.83 An actual transfer is not required.84 The date on which titleReferences(p. 227) changes will normally be the date on which the treaty comes into force:85 an unratified treaty does not confer sovereignty.86 Naturally the transferee cannot receive any greater rights than those possessed by the transferor: nemo dat quod non habet.87
Apart from cession and transfer in accordance with a treaty, title may exist on the basis of a treaty alone, the treaty marking a reciprocal recognition of sovereignty in solemn form.88 In the case of a disputed frontier the boundary treaty which closes the dispute will create title, previously unsettled, whereas a treaty of cession merely transfers an extant (though definitive) title.89 In the case where a territorial regime is established by a treaty, this settlement achieves a permanence which the treaty itself does not necessarily enjoy: the continued existence of that regime is not dependent upon the continuing life of the treaty under which the regime is agreed.90
(i) Agreements concluded with indigenous rulers91
In substance, it is not an agreement between equals; it is rather a form of internal organisation of a colonial territory, on the basis of autonomy of the natives…And thus suzeraintyReferences(p. 228) over the native States becomes the basis of territorial sovereignty as towards other members of the community of nations.94
Subsequent decisions of the International Court have qualified Huber’s dictum to a degree. In Western Sahara the Court stated that in the period beginning in 1884, ‘agreements with local rulers, whether or not considered as an actual “cession” of the territory, were regarded as derivative roots of title, and not original titles obtained by occupation of terra nullius’.95
In Cameroon v Nigeria, the Court was called upon to determine the legal effect of an 1884 treaty between the UK and the ‘Kings and Chiefs of Old Calabar’, an area in the Niger Delta, and its consequent effect on the UK’s capacity to deal later with the ter-ritory.96 Nigeria considered the 1884 treaty to have created an international protectorate, which did not therefore result in the transfer of title to the UK; rather it remained vested in Old Calabar as a sovereign entity. The Court disagreed, noting that: (a) at the time, the UK did not regard Old Calabar as a state, a position consistent with its activity in the rest of the region; (b) the region did not possess a central federal authority sufficient to create a protectorate; (c) British activity in the region was reflective of an intention to administer, rather than merely protect; and (d) Nigeria was unable to identify with any degree of precision the source and character of Old Calabar’s international personality, either in 1884 or thereaft er.97The Court concluded that ‘under the law at the time, Great Britain was in a position in 1913 to determine its boundaries with Germany in respect of Nigeria, including in the southern section’.98
(ii) Renunciation or relinquishment
It is possible for states to renounce title over territory in circumstances in which the subject-matter does not thereby become terra nullius. This distinguishes renunciation from abandonment. Furthermore, there is no element of reciprocity, and no commitment to transfer, as in the case of a treaty of cession. Renunciation may be recognition that another state now has title99 or an agreement to confer a power of disposition to be exercised by another state or a group of states.100
References(p. 229) A series of unilateral acts may constitute evidence of an implicit relinquishment of rights.101Renunciation is to be distinguished from reversion, that is, recognition by an aggressor that territory seized is rightfully under the sovereignty of the victim. Here, there is no title to renounce.102
(E) Adjudication
While the subject is generally neglected, some jurists accept adjudication by a judicial organ as a mode of acquisition.103 The question then, as with a treaty of cession, is whether the award is self-executing, or merely gives an executory right.104 At least in certain cases the award is dispositive as between the parties: (a) when the character of the territory is such that no physical act is necessary to its effective appropriation (this is true of maritime delimitations); (b) where the two disputants are both exercising acts of administration in respect of the territory concerned and the award merely declares which of the two ‘possessors’ is a lawful holder; (c) where the loser is to continue in possession with delegated powers of administration and jurisdiction; (d) when the successful claimant is already in possession; and (e) (perhaps) where the award relates only to the detailed fixing of a frontier line.105
4. Displacement of Title
(A) The Concept of ‘Prescription’106
(i) The place of prescription in the law
At its core, prescription refers to the removal of defects in a putative title arising from usurpation of another’s sovereignty by the acquiescence of the former sovereign. The standard apology for the principle rests on considerations of good faith and the needReferences(p. 230) to preserve international order and stability. It is inelegant to describe it as a mode of acquisition: the real source of title is recognition of or acquiescence in the consequences of unchallenged possession and control.
Prescription is distinct from the outright abandonment or relinquishment of territory. Abandonment refers to a situation where a state is held to have surrendered its title, converting the territory to res nullius, before another state establishes its own title by way of lawful allocation or effective occupation. In the case of abandonment, there is no usurpation of sovereignty since there are no contemporaneous competing claims.107Relinquishment is the giving up of a claim to territory in face of what is thereby acknowledged to be a better claim, or at least a subsisting one.108
In particular cases the difference between prescription and effective occupation is not easy to establish. In Island of Palmas and cases like it, there is simply contemporaneously competing state activity: in deciding on title the tribunal will apply the criterion of effective control associated with ‘effective occupation’.109 To speak of prescription is unhelpful,110 and significantly Huber avoided the term, apart from a passing reference to ‘so-called prescription’, by which he meant merely ‘continuous and peaceful display of State sovereignty’.
(ii) The role of private law analogies
In addressing problems of prescription, writers have drawn on analogies from the private law of both civil and common law traditions.111 From the civilian tradition has been drawn the concept of abandonment or derelictio, under which the title-holder makes a conscious decision to relinquish its rights with respect to the contested territory, which may result in its becoming res nullius prior to the assertion of the other state’s claim. From the common law comes the doctrine of estoppel, under which a representation made by one state that is relied on by another to its detriment may preclude the former state from acting in a contrary fashion. Another, now declining, source of analogy has been the civil law doctrine of acquisitive prescription and the common law ‘equivalent’ of adverse possession.112
References(p. 231) Apart from the imperfect nature of these ‘sources’, there is the distinct issue of the effect of the presumption of legality. Analogies with municipal law reveal the difficulty with any general doctrine of prescription. Although it is sometimes said that the International Court would accept acquisitive prescription as a general principle of law,113 what is the content of the general principle? Instead of providing guidance, analogies to acquisitive prescription, adverse possession or similar concepts tend to spark confusion and lead to inconsistent terminology.114
(B) The Requirements of Prescription
(i) Conduct on the part of the usurping party
To establish such a case for the usurpation of title, certain prerequisites need to be clearly established.115
(1) Possession must be exercised à titre de souverain. There must be a display of state authority and the absence of recognition of sovereignty in another state, for example under conditions of a protectorate leaving the protected state with a separate personality. Without adverse possession there can be no prescription.
(2) The possession must be public, peaceful, and uninterrupted. As Johnson has remarked: ‘Publicity is essential because acquiescence is essential’.116By contrast in a situation of competing state activity, as in Island of Palmas, publicity will not play an important role because acquiescence may not be relevant except in minor respects.
(3) Finally, possession must persist. In the case of recent possession it is difficult to adduce evidence of tacit acquiescence. A few writers have prescribed fixed periods of years.117Such suggestions are due to a yearning after municipal models and to the influence of the view that ‘acquiescence’ may be ‘implied’ in certain conditions. The better view is that the length of time required is a matter of fact depending on the particular case.118
References(p. 232) Where the necessary effectivités on the part of the usurping party have been established, the competing conduct of the title-holder must be assessed to determine whether title has been relinquished.