the Qatari captives in return for the safe passage of Mehmed Pasha's cavalry to Hofuf by land. Although Qatar did not gain full independence from the Ottoman Empire, the result of the battle forced a treaty that would later form the basis of Qatar emerging as an autonomous separate country within the empire. Later Ottoman presence On the cusp of Ottoman withdrawal from the Peninsula in 1915, the British government wrote the following description of the Ottoman presence in Qatar: British protectorate (1916–1971) The Ottomans officially renounced sovereignty over Qatar in 1913, and in 1916 the new ruler Abdullah bin Jassim Al Thani signed a treaty with Britain, thereby instating the area under the trucial system. This meant that Qatar relinquished its autonomy in foreign affairs, such as the power to cede territory, and other affairs, in exchange for Britain's military protection from external threats. The treaty also had provisions suppressing slavery, piracy, and gunrunning, but the British were not strict about enforcing those provisions. Despite Qatar coming under British protection, Abdullah bin Jassim's position was insecure. Recalcitrant tribes refused to pay tribute; disgruntled family members intrigued against him; and he felt vulnerable to the designs of Bahrain and the Wahhabi. The Al Thani were merchant princes, reliant on trade and especially the pearl trade, and dependent on other tribes to do their fighting for them, primarily the Bani Hajer who owed their allegiance to Ibn Saud, amir of the Najd and Al-Hasa. Despite numerous requests by Abdullah bin Jassim for strong military support, weapons, and a loan, the British were reluctant to become involved in inland affairs. This changed in the 1930s, when competition for oil concessions in the region intensified. Oil drilling The scramble for oil raised the stakes in regional territorial disputes and signified the need to establish territorial borders. The first move came in 1922 at a boundary conference in Uqair when prospector Major Frank Holmes attempted to include Qatar in an oil concession he was discussing with Ibn Saud. Sir Percy Cox, the British representative, saw through the ploy and drew a line on the map separating the Qatar Peninsula from the mainland. The first oil survey took place in 1926 under the direction of George Martin Lees, a geologist contracted to the Anglo-Persian Oil Company, but no oil was found. The oil issue raised its head again in 1933 after an oil strike in