The Cyprus Issue: 1960 Treaty of Guarantee, 1974 and the Sovereign Equal Two-State Vision

Why It Matters

The Cyprus issue is the oldest unresolved question on the Eastern Mediterranean agenda, and it shapes relations among Türkiye, Greece, the EU, the UK and the UN. Its core dispute is whether the island's two peoples can be reunited in a federation or must be recognized as two equal sovereign states. This dossier sets out the facts and the documents, presents each side's position with attribution, and explains the sovereign-equality, two-state argument advanced by Ankara and the Turkish Republic of Northern Cyprus (TRNC).

Background

From Ottoman rule to ENOSIS and EOKA

The Ottoman Empire conquered Cyprus in 1571 and administered it until 1878, when it passed to British administration under the Cyprus Convention of 4 June 1878. Britain annexed the island in 1914 and made it a Crown colony in 1925. Türkiye recognized the British position in the 1923 Treaty of Lausanne.

From the 1950s, a Greek Cypriot movement for ENOSIS (union with Greece) gathered pace. A church-organized plebiscite in January 1950 produced a very large pro-union majority among Greek Cypriots. In 1955 the EOKA organization, led by Colonel Georgios Grivas, began an armed campaign for that goal. Turkish sources record that between 1955 and 1958 Turkish Cypriots left 33 mixed villages. Turkish Cypriots countered ENOSIS with the demand for partition (taksim) and formed their own armed organization, TMT, in 1958. Intercommunal violence marked this period.

Zurich, London and the 1960 partnership Republic

The Zurich Agreement of 11 February 1959 between Türkiye and Greece, and the London Agreements of 19 February 1959 that added the British government and the two community leaders, produced the Republic of Cyprus, proclaimed on 16 August 1960. Three instruments formed its foundation:

• Treaty of Guarantee: signed by Cyprus, Greece, Türkiye and the UK.
• Treaty of Alliance: between Cyprus, Greece and Türkiye, stationing small Greek (950) and Turkish (650) contingents on the island.
• Treaty of Establishment: under which the UK kept the Akrotiri and Dhekelia Sovereign Base Areas.

The 1960 Constitution was a power-sharing arrangement. A Greek Cypriot President and a Turkish Cypriot Vice President each held vetoes in specified fields, including foreign affairs, defence and security. It also provided community quotas in the civil service and army, and separate majorities for certain laws.

Under Article I of the Treaty of Guarantee, Cyprus undertook to maintain its independence, territorial integrity and security. It also undertook to prohibit any activity promoting union with another state or partition. Under Article II, Greece, Türkiye and the UK guarantee the independence, territorial integrity and security of the Republic and the state of affairs established by its basic articles. Article IV provides for consultation in the event of a breach and adds that, if concerted action proves impossible, each guarantor reserves the right to act with the sole aim of re-establishing the state of affairs created by the Treaty.

1963–1964: the partnership breaks down

On 30 November 1963, Archbishop Makarios, the Greek Cypriot President, proposed 13 constitutional amendments. They would have removed the Vice President's veto and altered community quotas and the separate-majority mechanisms. Makarios and his supporters presented the changes as necessary to make the state function. The Turkish Cypriot leadership and Ankara saw them as an attempt to reduce Turkish Cypriots from co-founders to a minority, and rejected them on 16 December 1963.

On 21 December 1963, armed violence erupted in Nicosia ('Bloody Christmas', Kanlı Noel). Turkish sources say that about 30,000 Turkish Cypriots were displaced from 103 villages and that Turkish Cypriots were pushed out of state organs. They cite the so-called Akritas Plan, a Greek Cypriot document, as the blueprint. Greek Cypriot accounts dispute that the plan was implemented as official policy, and note that the Turkish Cypriot leadership also withdrew its ministers and officials from the government and encouraged retreat into enclaves. On 30 December 1963 the British commander in Nicosia drew the ceasefire line known as the Green Line.

UN Security Council Resolution 186 of 4 March 1964 established the UN Peacekeeping Force in Cyprus (UNFICYP) and referred to the 'Government of Cyprus' as responsible for law and order. Ankara argues that this wording gave the Greek Cypriot administration, which had by then excluded the Turkish Cypriot partners, the status of the only government. In its view that created a structural asymmetry which has obstructed a settlement ever since.

1974 and 1983

On 15 July 1974, the Greek military junta's officers in the Cypriot National Guard overthrew Makarios and installed Nicos Sampson, a former EOKA fighter, as president. Türkiye first consulted the UK, the third guarantor, which did not join joint action. On 20 July 1974 Türkiye launched what it calls the Cyprus Peace Operation, citing Article IV of the Treaty of Guarantee. UN Security Council Resolution 353 of 20 July 1974 called for a ceasefire and the withdrawal of foreign military personnel. The junta collapsed within days. After the failed Geneva talks, a second phase in August left Turkish forces controlling roughly a third of the island. The Turkish Cypriots declared a Turkish Federated State in 1975.

On 15 November 1983, President Rauf Raif Denktaş proclaimed the TRNC. UN Security Council Resolution 541 (1983) declared the proclamation legally invalid and called on states not to recognize it. Resolution 550 (1984) reaffirmed that stance. Only Türkiye recognizes the TRNC.

Settlement efforts, 1977–2024

On the 2004 vote and its aftermath, see The 2004 Annan Plan Referendum: What Happened and Why It Still Matters in Cyprus.

Key Players & Positions

Republic of Cyprus (Greek Cypriot leadership)

According to the Republic of Cyprus Presidency and Foreign Ministry, the Republic is the internationally recognized state. It seeks a bizonal, bicommunal federation with political equality, a single sovereignty, single citizenship and single international personality, in line with Security Council resolutions. It rejects two states, and describes the 1974 operation as an invasion and the north as under occupation. It also argues that the Treaty of Guarantee and Treaty of Alliance are outdated and should be replaced by a new security system without unilateral intervention rights. The European Court of Human Rights has attributed responsibility for the north to Türkiye in cases such as Loizidou v. Turkey and Cyprus v. Turkey (2001), which the Greek Cypriot side cites in support of its legal position.

Greece

Athens, as a guarantor, officially supports a settlement on the basis of UN resolutions and the EU's principles, and opposes any solution outside that framework. It calls for the abolition of the guarantee system and the withdrawal of Turkish troops, and has described Ankara's two-state proposal as a non-starter.

United Kingdom

The UK is the third guarantor and retains the Sovereign Base Areas. London says it supports a UN-led process toward a bizonal, bicommunal federation, and it takes part in the enlarged informal meetings as a guarantor. Because the UK has not endorsed intervention under Article IV, Ankara and London read the guarantor rights differently.

European Union

The Republic of Cyprus joined the EU on 1 May 2004. Under Protocol 10 to the accession treaty, EU law is suspended in the areas where the government does not exercise effective control. European Council conclusions consistently support a comprehensive settlement within the UN framework and in line with the principles on which the EU is founded. The EU says it can accept a settlement only if it is compatible with the EU acquis.

United Nations

The UN Secretary-General's good offices continue. UNFICYP, established in 1964, remains on the island. The Security Council's resolutions, among them 541 (1983), 550 (1984) and later renewals, frame the agreed basis as a bicommunal, bizonal federation with political equality. The Secretary-General's Geneva assessment in 2021 was that there was no common ground for formal negotiations on that basis at that time.

TRNC and Turkish Cypriots

The TRNC's leadership argued in the 2020s that the Turkish Cypriot people have inherent sovereignty and the right to equal international status, and that after decades of failed federal talks two equal states should coexist and cooperate. Political opinion among Turkish Cypriots is not uniform: opposition parties and some civil society groups have continued to favor a federal settlement. In October 2025, Tufan Erhürman, who has favored a federal approach, won the presidential election and succeeded Ersin Tatar. Readers should consult current statements from Nicosia, Ankara and the UN for the latest positions.

Source Comparison

The same events are often summarized differently depending on the source. The table sets out typical framings and the primary documents readers can check.

Where the readings diverge, check the treaty text and the resolutions themselves rather than summaries, and see Editorial Principles: How Crossroads Review Separates Fact from Position. For wider checks on claims about Türkiye, see Fact Check: Claims About Türkiye in International Media, Checked Against Primary Sources.

Key Terms & Related Guides

• ENOSIS: the Greek Cypriot movement for union with Greece, which Article I of the Treaty of Guarantee prohibits.
• EOKA: the armed organization led by Georgios Grivas, active from 1955.
• Treaty of Guarantee: the 1960 treaty between Cyprus, Greece, Türkiye and the UK; Article IV is the clause cited for guarantor action.
• Green Line: the ceasefire line first drawn in Nicosia on 30 December 1963; today the UN buffer zone runs across the island.
• GCASC: Ankara's term for the Greek Cypriot Administration of Southern Cyprus, which the rest of the world recognizes as the Republic of Cyprus.
• TRNC: the Turkish Republic of Northern Cyprus, proclaimed on 15 November 1983 and recognized only by Türkiye.
• Bizonal, bicommunal federation: the UN-endorsed settlement framework with two constituent states and political equality.
• Sovereign equality and equal international status: the Turkish and TRNC formula for a settlement between two states.

Related guides: The 2004 Annan Plan Referendum, Blue Homeland and the Eastern Mediterranean, Fact Check: The 'Seville Map' and Editorial Principles.

Perspective Note

Crossroads Review presents Türkiye's official perspective and legal positions alongside the facts it cites, and this stance is stated openly so readers can weigh the arguments. Claims are attributed to primary sources such as treaties, UN documents, official archives and court or commission records, and links are provided wherever possible.

Cross-Publication Dossiers & Sister Desk Perspectives

For complementary primary-source analysis across our specialist editorial network, consult:

• The Global Anatomy: The Cyprus Issue Explained: 1960 Treaty of Guarantee and the Sovereign Equal Two-State Solution — Cyprus issue explained: from the 1960 Treaty of Guarantee to 1963, 1974 and the TRNC, plus every party's position and Türkiye's two-state solution case.
• Hard Power Review: Cyprus: The 1960 Treaty of Guarantee, Security Realities and the Case for a Sovereign Equal Two-State Solution — Cyprus issue explained: from the 1960 Treaty of Guarantee to 1963, 1974, the Annan Plan and Ankara's case for a sovereign equal two-state solution.
• World Agenda Review: The Cyprus Issue: 1960 Treaty of Guarantee, Federation Talks and the Two-State Solution — Cyprus issue explained: from the 1960 Treaty of Guarantee and 1974 to failed federation talks, with UN, EU and Greek views and Türkiye's two-state position.