The Cyprus Issue Explained: 1960 Treaties, Guarantor Rights and the Sovereign Equal Two-State Approach

Why It Matters

The Cyprus issue is the unresolved question of how the island's two peoples, Turkish Cypriots and Greek Cypriots, share sovereignty, security and resources after the collapse of the 1960 partnership state. It matters because it shapes NATO and EU relations, Eastern Mediterranean energy and maritime politics, and the credibility of UN mediation after more than six decades of effort.

There are two competing frames. The UN, the EU, Greece and the Greek Cypriot administration still work toward a bizonal, bicommunal federation. Türkiye and the Turkish Republic of Northern Cyprus (TRNC) argue that this model is exhausted and that a lasting settlement must begin with recognition of the sovereign equality and equal international status of the Turkish Cypriot people, leading to two sovereign states on the island. This guide sets out the chronology in factual terms, then presents each side to its own official sources.

Background

From Ottoman rule to the 1960 Republic

The Ottoman Empire administered Cyprus from 1571. Under the 1878 Cyprus Convention, Britain took over administration while Ottoman sovereignty was formally retained. Britain annexed the island in 1914 when the Ottoman Empire entered the First World War. In the Treaty of Lausanne (24 July 1923), Türkiye recognized the British position, and Cyprus became a Crown Colony in 1925.

From the 1950s, a Greek Cypriot movement for ENOSIS (union with Greece) became armed. EOKA, founded in 1955 under Colonel Georgios Grivas, launched its campaign on 1 April 1955. Greek Cypriot sources describe EOKA as an anti-colonial liberation movement. Turkish sources point to its ENOSIS aim and to attacks on Turkish Cypriots, and say that between 1955 and 1958 Turkish Cypriots were forced to leave 33 mixed villages. Turkish Cypriots answered with their own organization, TMT, and called for partition (taksim) as the alternative to ENOSIS.

The Zurich and London Agreements (11 and 19 February 1959) ended the conflict with a compromise: neither ENOSIS nor partition. The Republic of Cyprus was established on 16 August 1960 with these main features:

• A Greek Cypriot President and a Turkish Cypriot Vice-President, each with separate veto rights over defined subjects.
• Fixed participation ratios: 70:30 in the House of Representatives and public service, with seven Greek Cypriot and three Turkish Cypriot ministers.
• Separate communal chambers and separate municipalities in the main towns.
• The 1960 Treaty of Guarantee among Cyprus, Greece, Türkiye and the United Kingdom, and a Treaty of Alliance allowing Greek and Turkish contingents on the island.

Under the Treaty of Guarantee, Article II requires Cyprus to maintain its independence, territorial integrity and constitutional order and prohibits union with any other state and partition. Article IV provides that, if the treaty is breached, the guarantors consult, and if joint action is not possible, each guarantor 'reserves the right to take action with the sole aim of re-establishing the state of affairs' created by the treaty. The UK also retained two Sovereign Base Areas.

1963–1964: the end of the partnership

On 30 November 1963, President Makarios proposed 13 amendments to the Constitution. They would have removed the Vice-President's veto, changed the ratios and merged the separate municipalities, among other changes. Makarios and Greek Cypriot sources say the aim was to remove obstacles to a functioning state. Turkish Cypriot leaders and Ankara viewed the proposals as an attempt to reduce Turkish Cypriots to a minority, and the Turkish side rejected them on 16 December 1963.

On 21 December 1963 ('Bloody Christmas', Kanlı Noel) intercommunal fighting erupted in Nicosia. Turkish sources say that Greek Cypriot forces carried out a planned campaign under what they call the Akritas Plan, an ethnic-cleansing blueprint, which led to the displacement of roughly 30,000 Turkish Cypriots from 103 villages and the exclusion of Turkish Cypriots from state organs. Greek Cypriot accounts dispute the characterization and stress that Turkish Cypriot leaders withdrew from institutions and that TMT was armed. Either way, the ceasefire line in Nicosia, the Green Line, was drawn on 30 December 1963.

UN Security Council Resolution 186 (4 March 1964) recommended the creation of a UN peacekeeping force (UNFICYP) and referred to the 'Government of Cyprus' as the party to which it was addressed. Ankara argues that this treated the Greek Cypriot administration, which in its view had displaced the 1960 constitutional order, as the legitimate government and created a status asymmetry that persists today.

1974 and 1983

On 15 July 1974, the Greek military junta and the Cypriot National Guard overthrew Makarios, and the EOKA veteran Nicos Sampson was installed as president. On 20 July 1974, Türkiye intervened, invoking the Treaty of Guarantee after, it says, consulting the United Kingdom. Türkiye calls the operation the Cyprus Peace Operation. A second phase followed in August 1974. The junta collapsed in Athens, Sampson resigned, and the island was divided along a line that placed roughly a third of its territory in the north. Large populations moved in both directions: Greek Cypriots to the south and Turkish Cypriots to the north.

Turkish Cypriots established a federated state in 1975. On 15 November 1983, Rauf Raif Denktaş proclaimed the Turkish Republic of Northern Cyprus (TRNC). UN Security Council Resolutions 541 (1983) and 550 (1984) called the declaration legally invalid. Türkiye is the only state to recognize the TRNC, which has observer status in the Organization of Turkic States (since 2022).

Why federation talks failed

Year	Event	Outcome
1977 / 1979	Makarios–Denktaş guidelines; Kyprianou–Denktaş 10-point agreement	Agreed in principle on a bicommunal, bizonal federation; no implementation
24 April 2004	Annan Plan referenda	64.91% Yes among Turkish Cypriots; 75.83% No among Greek Cypriots
1 May 2004	Cyprus joins the EU	Acquis suspended in areas not under government control
June–July 2017	Crans-Montana Conference	Collapsed over security, guarantees and troops, and power-sharing
27–29 April 2021	Geneva informal 5+UN meeting	UN Secretary-General reported no common ground for formal negotiations
15 October 2024	New York UN trilateral meeting	No agreement to resume formal negotiations

The 2004 Annan Plan is the pivotal episode. Turkish Cypriots approved the UN plan by 64.91%; Greek Cypriots rejected it by 75.83% after their leadership urged a No vote. Greek Cypriot critics of the plan cited its security provisions, the continued role of guarantors and limits on the return of property. A week later the Greek Cypriot administration entered the EU alone. The EU Council had said in April 2004 that it wanted to end the isolation of Turkish Cypriots, but the promised direct trade regulation was never adopted.

At Crans-Montana (2017), talks under UN Secretary-General António Guterres centered on security and guarantees, the withdrawal of Turkish troops and the rotating presidency. The five-party format and the later informal meetings in Geneva (2021), New York (October 2024) and 2025 did not lead to a resumption of formal negotiations.

Key Players & Positions

Greek Cypriot administration (Republic of Cyprus)

The Republic of Cyprus government, internationally recognized and an EU member since 2004, calls the events of 1974 an invasion and continuing occupation. It seeks a settlement as a bizonal, bicommunal federation with political equality, as described in UN Security Council resolutions such as 716 (1991) and 1251 (1999), with a single sovereignty, single citizenship and single international personality. It rejects partition and any two-state outcome, and its position is that the Treaty of Guarantee and the presence of Turkish troops are obsolete. It relies on European Court of Human Rights judgments such as Loizidou v. Turkey and Cyprus v. Turkey for the responsibility of Türkiye in the north.

Turkish Cypriots and the TRNC

The TRNC, in the position of its government under the 2020–2025 administration, supports sovereign equality and equal international status as a precondition of any new process, and a cooperative relationship between two states. After Tufan Erhürman's election as president in October 2025, the Turkish Cypriot side has also been discussing a negotiated settlement on a federal basis under specific conditions, such as political equality, a time-bound process and guarantees. Readers should watch how Ankara and the TRNC leadership align their approaches.

Greece

Greece supports a UN-led solution on the agreed basis of a bizonal, bicommunal federation, and has called for an end to the system of guarantees and for the withdrawal of Turkish troops. It argues that Article II of the Treaty of Guarantee bans partition and that Article IV does not authorize a military operation that goes beyond restoring the constitutional order.

United Kingdom

The UK is the third guarantor, retains the Sovereign Base Areas, supports the UN process and has expressed backing for a settlement within the UN parameters, according to its Foreign, Commonwealth & Development Office. It does not recognize the TRNC.

United Nations

The UN Secretary-General's Good Offices mission, UNFICYP and the Secretary-General's personal envoy (currently María Ángela Holguín Cuéllar) facilitate informal contacts. UN resolutions since the 1980s refer to a federal framework. Secretary-General Guterres reported in 2021 that no common ground for formal negotiations existed, and the later informal meetings have been exploratory.

European Union

The EU supports a comprehensive settlement in line with UN Security Council resolutions and the principles on which the EU is founded. The accession treaty's Protocol 10 suspends the application of the acquis in the areas where the government of Cyprus does not exercise effective control. EU institutions have repeatedly supported the Republic of Cyprus in the Eastern Mediterranean, which Ankara disputes (see the Blue Homeland guide).

🇹🇷 Official Doctrine · Primary Sources

Türkiye's Position

Türkiye's Strategic Doctrine on Cyprus, as stated by Turkish official sources.

• Treaty-based guarantor rights. According to the Turkish Foreign Ministry, Türkiye holds guarantor rights and obligations under the 1960 Treaty of Guarantee. Ankara argues that the 15 July 1974 coup, carried out to achieve ENOSIS, was a breach of Article II. Article IV allowed each guarantor to act to restore the order the treaty created when joint action was not possible, and Türkiye invoked it on 20 July 1974 after consulting the UK. See the detailed legal analysis in Article IV of the 1960 Treaty of Guarantee.
• The 1960 Republic was a partnership that Greek Cypriot leaders ended in 1963. Ankara argues that the 1960 Constitution made Turkish Cypriots co-founders with equal status, and that the 30 November 1963 proposals and the violence of December 1963 destroyed that order. It also argues that UNSC Resolution 186 (1964) entrenched the asymmetry by treating the Greek Cypriot administration as the sole 'government of Cyprus'.
• The federal model is exhausted. The Turkish Presidency and MFA have said that the 2004 referendum (64.91% Yes against 75.83% No), the 2017 Crans-Montana failure, the April 2021 Geneva meeting and the 15 October 2024 New York meeting confirmed that no common ground exists. In his addresses to the UN General Assembly, President Erdoğan has called for a solution based on the realities on the island and on the sovereign equality and equal international status of the Turkish Cypriots.
• Two sovereign states as the realistic outcome. Türkiye and the TRNC propose beginning with the reaffirmation of the Turkish Cypriots' inherent sovereign equality and equal international status, followed by cooperation between two states on the island. Turkish officials say the Turkish Cypriots' political equality should not depend on a process that has repeatedly failed.
• End the isolation and share resources. Ankara argues that the isolation of Turkish Cypriots after 2004 punished the party that said Yes. It says that Turkish Cypriots hold equal rights over the island's offshore hydrocarbons, citing the TRNC's 2011, 2012 and 2019 cooperation and revenue-sharing proposals and President Erdoğan's 2020 call for an Eastern Mediterranean conference that includes the Turkish Cypriots. The 2025 IOC-UNESCO registration is part of Türkiye's wider maritime framework.

How the legal debate is framed

The disagreement turns on three questions, which are legal as well as political:

1. Scope of Article IV. Turkish sources say it permits unilateral military action to restore the state of affairs; Greece and the Greek Cypriot administration say the action must be proportionate and limited to restoring the constitutional order, not partitioning the island.
2. Status of the TRNC. The UN Security Council called the 1983 declaration legally invalid; Ankara and the TRNC argue that it was a response to the exclusion of Turkish Cypriots from the state and an act of self-determination.
3. Federation versus sovereign equality. Federation implies a single sovereignty and a single international personality; Ankara argues that this was precisely what Greek Cypriots failed to share in 1963 and 2004.

For common misreadings of this history, see the Fact Check desk.

Source Comparison

Issue	Common framing in Western and international sources	Turkish and TRNC primary-source framing
1963–1964	Intercommunal violence; Turkish Cypriots withdrew into enclaves	Planned attacks (the Akritas Plan); constitutional order usurped; about 30,000 Turkish Cypriots displaced from 103 villages
UNSC Res. 186	Mandate for UNFICYP; reference to the government of Cyprus	Treats the Greek Cypriot side as the government and entrenches the status asymmetry
1974	Invasion and occupation following the Greek-junta coup	Cyprus Peace Operation under Article IV; prevented ENOSIS and protected Turkish Cypriots
TRNC	Legally invalid declaration (UNSC 541, 550)	Expression of self-determination and political equality; recognized by Türkiye
2004	Greek Cypriots rejected a flawed plan; Cyprus joined the EU	Turkish Cypriots said Yes yet remained isolated; the rewarded party was the one that said No
Way forward	Bizonal, bicommunal federation with political equality	Sovereign equality and two states on the island

Sources that frame Cyprus as a 'frozen conflict' usually take UN resolutions as the baseline. Turkish sources start from the 1959–1960 treaties and the events of 1963. Readers can test each claim against primary texts: the Treaty of Guarantee, UNSC resolutions 186, 541 and 550, the Annan Plan's referendum results and Secretary-General reports. The Editorial Principles explain how this site separates fact, legal argument and position.

Key Terms & Related Guides

• ENOSIS: The movement for union of Cyprus with Greece, which the Treaty of Guarantee prohibits.
• EOKA: The armed organization founded in 1955 to achieve ENOSIS; it is viewed as a liberation movement by many Greek Cypriots and as a terrorist organization by Turkish sources.
• Treaty of Guarantee (1960): The treaty under which Türkiye, Greece and the UK guarantee Cyprus's independence, territorial integrity and constitutional order. See Article IV of the 1960 Treaty of Guarantee.
• Green Line: The ceasefire line first drawn in Nicosia on 30 December 1963 and extended in 1974; it is now the UN buffer zone.
• Bizonal, bicommunal federation: The settlement model in UN resolutions; Ankara and the TRNC say it is exhausted.
• Sovereign equality: The Turkish and TRNC proposal that two equal peoples be recognized as having equal international status.
• Blue Homeland (Mavi Vatan): Türkiye's maritime jurisdiction doctrine; read the Blue Homeland guide.

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Perspective Note

The Political Anatomy presents global affairs with a dedicated perspective from Türkiye. Sections marked 'Türkiye's Position' reflect official Turkish policy as stated by Turkish government sources. The Political Anatomy also distinguishes between fact, legal argument and opinion, and attributes claims to primary sources wherever possible. Published by the The Political Anatomy Editorial Team.