Treaty of Ankara Summary

  • Last updated on November 10, 2022

The contentious Mosul question involved the issue of whether the oil-rich region of northern Iraq should return to Turkish sovereignty or be transferred permanently to British-mandated Iraq after World War I.

Summary of Event

Following the victorious Allies’ armistice agreement with the defeated Ottoman Empire at Moudros on October 30, 1918, and the stillborn Treaty of Sèvres of August 10, 1920, Sèvres, Treaty of (1920) the amending Treaty of Lausanne of July 24, 1923, Lausanne, Treaty of (1923) with the Turkish Republic failed to set a definitive, internationally agreed-upon border between Turkey and the new, League of Nations-approved, British-mandated territory of Iraq. The latter was created from three former Ottoman provinces in Mesopotamia, including the northern province of Mosul. However, when the Treaty of Lausanne was ratified on August 6, 1924, it left open the possibility of referring the border issue to the League of Nations if Britain and Turkey could not find an amicable settlement to the matter within nine months. [kw]Treaty of Ankara (July 18, 1926) [kw]Ankara, Treaty of (July 18, 1926) Mosul question Ankara, Treaty of (1926) League of Nations;Mosul question [g]Iraq;July 18, 1926: Treaty of Ankara[06680] [c]Diplomacy and international relations;July 18, 1926: Treaty of Ankara[06680] [c]Expansion and land acquisition;July 18, 1926: Treaty of Ankara[06680] Aras, Tevfik Rüştü Barzanjī, Maḥmūd Cox, Sir Percy Zachariah Lindsay, Sir Ronald Charles Nūrī al-Saՙīd

The two parties were unable to agree on the border’s placement at Lausanne because the Turkish representatives repeatedly claimed sovereignty over Mosul from 1923 through 1926. They based their claims on geographic, demographic, ethnographic, historic, economic, and other issues, including the alleged political wishes of the province’s Turkish and Kurdish speakers, whose numbers and ethnicities could not be accurately determined. The Turks demanded that the border (and thus the sovereignty) issue be settled by plebiscite among the approximately 700,000 inhabitants of the province, who were anchored primarily around the cities of Mosul, Kirkuk, Arbīl, and as-Sulaymānīyah and the surrounding countryside. For its part, Britain claimed priority for the right of conquest, which the Turks characterized as an outdated principle of international law and mandatory power that they refused to recognize.

Following an inconclusive conference in Constantinople in May of 1924, an armed clash between the two confronting armies in Mosul became a real possibility. The British submitted the issue to the Council of the League of Nations in September of 1924, and the League established a commission of inquiry composed of Af de Wirsén of Sweden (a neutral country), the committee’s chairman; Count Paul Teleki of Hungary, previously aligned with the Central Powers and the Ottoman Empire; and Colonel A. Paulis of Belgium (an Allied country). After visiting London and Ankara, the commission went to Baghdad and Mosul, where members conducted numerous interviews and surveys. The three-member commission then presented its report to the League of Nations.

Although the report was ambiguous in many respects—it often wavered between favoring Turkish sovereignty and favoring British sovereignty—the Commission finally awarded control to British-mandated Iraq. Accordingly, the League of Nations Council granted Mosul Province to Iraq on October 29, 1924. The Turks, however, challenged the binding nature of the League Council’s determination of the so-called Brussels line, the provisional border that awarded Mosul to Iraq. In response, the Council sought the advice of the Permanent Court of International Justice, which opined that the award was indeed arbitral rather than mediational or recommendatory so long as the League Council’s decision, ignoring the self-interested British and Turkish votes, was unanimous. The League Council thus endorsed the award of Mosul to Iraq on December 16, 1925.

Turkey reluctantly assented to the decision on June 5, 1926, through the Treaty of Ankara, which was ratified on July 18, 1926. As a sop to Turkish nationalist sensitivities, the British-advised Iraqi government committed itself to paying Turkey 10 percent of all royalties from the Turkish Petroleum Company (which had obtained the concession for all oil operations in Mosul on March 14, 1925) for a period of twenty-five years. On that basis, Turkey eventually collected 3,685,536 Iraqi dinars between 1931 and 1951, when the provision expired. Meanwhile, as the Turkish-British dispute was unfolding, a heated rivalry grew among various Kurdish tribal leaders for ascendancy and power. These Kurds came to oppose the British presence, and one of them, Sheikh Maḥmūd Barzanjī, alternated between supporting the British and opposing them after declaring himself king of Kurdistan.

The reluctant Turks accepted the League Council’s decision without engaging in battle for several reasons. First, the new Turkish Republic wished to consolidate its internal power after termination of the Ottoman sultanate and caliphate. Second, the Turks were weary following their bloody 1919-1923 war with Greece, in which the Greeks invaded Anatolia in the hope of collecting the reward promised to them by the Allies during World War I. At the time, there was uncertainty about promised Soviet aid to Turkey. Finally, and perhaps most important, Turkish diplomats such as Foreign Minister Tevfik Rüştü Aras realized that the balance of power in the League Council lay with the victorious Allied members, who were broadly represented, in contrast to the defeated ones (such as Turkey), who were not.





The British, encouraged by Sir Percy Zachariah Cox, a senior British negotiator, were not about to give up their controlling interest in much of the oil discovered in Mosul. Accordingly, when the Treaty of Ankara was signed by Sir Ronald Charles Lindsay, Britain’s ambassador to Turkey; Colonel Nūrī al-Saՙīd, acting Iraqi minister of national defense; and Tevfik Rüştü Aras, the signatories confirmed the border adopted by the League of Nations at its session of October 29, 1924—the Brussels line—with minor modifications to be recommended by a boundary commission to be established soon after the treaty’s signature.


Long after the “definitive” settlement of the Mosul question by the Treaty of Ankara of June 5, 1926, the delineation of Mosul’s border with Turkey—like Iraq’s other artificial borders, which were remnants of its colonial rule—continued to cause conflict. The League’s neglect of Kurdish aspirations to national self-determination (which the Kurds had expected to achieve under U.S. president Woodrow Wilson’s Fourteen Points) resurfaced after the first Persian Gulf War in 1991.

Kurds in Mosul, who lived in semiautonomy after the defeat of Iraqi president Saddam Hussein’s central government in 1991, started to infiltrate the porous Turkish border to support their Kurdish brethren’s insurgency against the Ankara government. Some thirty-five thousand Turkish troops crossed into northern Iraq in hot pursuit of the Kurdish fighters of the militant Kurdish Workers Party—the PKK—in May of 1995. On that occasion, Turkish president Süleyman Demirel and some of the media suggested that the border between the two countries should be redrawn. While the subsequent outcry muted those demands, the Kurds in Iraq, fearing strong Turkish opposition to the creation of an independent Kurdistan in Mosul, started to consider the possibility of a Kurdish-Turkish federation. Possibilities for this type of federation increased as some Kurds questioned whether they could find a niche within the new Iraqi regime after the ouster of Saddam Hussein in 2003. Under this scenario, Mosul would revert to Turkey, giving the Turks a strong bargaining chip—namely, non-Arab Mosul oil—in seeking admission into the European Union. Mosul question Ankara, Treaty of (1926) League of Nations;Mosul question

Further Reading
  • citation-type="booksimple"

    xlink:type="simple">Hurewitz, J. C., ed. The Middle East and North Africa in World Politics: A Documentary Record. 2d ed. Vol. 2. New Haven, Conn.: Yale University Press, 1979. Includes the texts of the Treaty of Lausanne of 1923 and the Treaty of Ankara of 1926. Contains introductory blurbs.
  • citation-type="booksimple"

    xlink:type="simple">Pipes, Daniel. “Hot Spot: Turkey, Iraq, and Mosul.” Middle East Quarterly 2, no. 3 (September, 1995): 65-68. Highlights how the contentious post-World War I delineation of the northern Iraqi border with Turkey had repercussions following Operation Desert Storm in 1991 and the loosening of Baghdad’s control over the Kurds.
  • citation-type="booksimple"

    xlink:type="simple">Polk, William R. Understanding Iraq. New York: HarperCollins, 2005. In his sweep of Iraqi history, this former American official and scholar evidences the ill-advised, imperialistically driven post-World War I settlements involving Iraq.
  • citation-type="booksimple"

    xlink:type="simple">Tripp, Charles. A History of Iraq. 2d ed. Cambridge, England: Cambridge University Press, 2002. Of particular interest is the section headed “The Mosul Question: Territory and Oil” in the extensive chapter titled “The British Mandate.”

Young Turks Stage a Coup in the Ottoman Empire

British Mount a Second Front Against the Ottomans

Great Britain and France Sign the San Remo Agreement

Great Iraqi Revolt

Permanent Court of International Justice Is Established

Iraqi Army Slaughters Assyrian Christians

Categories: History