In 1915–1916, British officials and Sharif Hussein of Mecca exchanged letters about Arab support against the Ottoman Empire in return for British backing of postwar Arab independence. The correspondence was written in broad, sometimes ambiguous terms about which territories would be included. These expectations later collided with secret Allied plans for dividing Ottoman lands.
British and French negotiators Mark Sykes and François Georges-Picot initialed a plan to divide Ottoman Arab provinces into planned zones of direct control and influence. The arrangement was designed for a postwar settlement and was kept secret from many partners, including Arab allies. It became a key reference point for later boundary discussions in the Levant.
In May 1916, the British and French governments formally approved the Sykes–Picot terms for dividing influence in the Arab provinces of the Ottoman Empire after World War I. The agreement envisioned a French-led northern zone (including much of Syria and Lebanon) and a British-led southern zone (including areas tied to Palestine and Mesopotamia). This ratification turned a negotiating concept into an official Allied plan.
Sharif Hussein’s forces launched the Arab Revolt in June 1916, fighting Ottoman rule with British support. The revolt made the question of who would govern former Ottoman Arab lands more urgent. It also strengthened Arab claims that wartime cooperation should lead to political independence rather than European partition.
On November 2, 1917, Britain issued the Balfour Declaration, supporting the establishment in Palestine of a “national home for the Jewish people,” while also stating that the rights of existing non-Jewish communities should not be harmed. This added a major new political promise affecting the southern Levant. It created another set of expectations that later influenced boundary and governance planning under the mandate system.
After the 1917 Russian Revolution, the Bolshevik government disclosed secret Allied agreements, including Sykes–Picot. The publication made the planned partition widely known and politically controversial. It deepened distrust among Arab leaders who had expected independence and highlighted contradictions among Allied wartime commitments.
In January 1919, Emir Faisal and Zionist leader Chaim Weizmann signed an agreement envisioning cooperation, with Faisal linking his support to Arab independence being fulfilled. The document reflected how different wartime promises were being combined—and contested—during postwar planning. It also showed that Palestine’s future was being debated alongside plans for a broader Syrian/Arab settlement.
In mid-1919, an American commission visited Syria and Palestine to assess public opinion on the postwar settlement. It reported strong support among many petitioners for a single independent Syria and significant opposition to a Zionist “national home” program as they understood it. Although the commission’s recommendations were not adopted by the main Allied powers, it documented how local preferences differed from European boundary plans.
In April 1920, the Allied Supreme Council at San Remo agreed on a mandate framework for former Ottoman territories. France was assigned the mandate for Syria and Lebanon, while Britain was assigned mandates for Palestine and Mesopotamia (Iraq). This decision translated wartime planning into an international governance structure that would shape later boundary-making.
In July 1920, French forces defeated Syrian troops at the Battle of Maysalun and soon entered Damascus. The defeat ended the short-lived Arab Kingdom of Syria and removed a major obstacle to implementing the French mandate. It also narrowed the political options for a unified post-Ottoman Syria and pushed boundary planning toward separate mandate territories.
In August 1920, the Treaty of Sèvres set out a peace settlement in which the Ottoman Empire renounced rights over much of its Arab territories. The treaty supported the mandate approach that the Allies had already advanced at San Remo. Although later replaced by the Treaty of Lausanne in 1923, Sèvres was part of the legal and diplomatic path that framed early boundary decisions.
On December 23, 1920, Britain and France signed a convention addressing practical issues for their mandates, including the general line and administration questions affecting the frontier between the Palestine and Syria/Lebanon mandates. This agreement moved boundary planning from wartime sketches toward implementable rules. It also set the stage for technical boundary commissions to map and demarcate lines on the ground.
By the end of the 1916–1920 planning period, Sykes–Picot’s basic concept—separating a French-led northern Levant from a British-led southern zone—had been reshaped into the mandate system through San Remo and subsequent agreements. The result was not a single final border line in 1920, but a durable administrative partition that later commissions refined into mapped frontiers. This framework became the starting point for many later state borders in the Levant and for long-running disputes tied to competing wartime promises.
In July 1922, the League of Nations approved the texts of the mandates for Palestine (Britain) and for Syria and Lebanon (France). The mandate documents embedded earlier political commitments into an international legal framework, including how the mandatory powers should administer the territories. This step helped lock in a partitioned Levant as separate mandate units, making boundary definition an administrative necessity rather than a hypothetical plan.
Sykes–Picot Agreement and boundary planning for the Levant (1916–1920)