Sheikh Abdullah Bin Qassim Al-Thani was born in 1880 at Doha. On 17 July 1913, Sheikh Abdullah became the ruler of Qatar. Britain and the Ottoman Empire accorded their recognition to Sheikh Abdullah and his successors’ as ruler over the whole of the Qatari Peninsula. The Ottoman also renounced all their rights to Qatar following the outbreak of the First World War; and Sheikh Abdullah forced the Ottomans to abandon Doha in 1915.  

On 3 November 1916, Britain signed a Treaty with Sheikh Abdullah in order to bring Qatar under its Trucial System of Administration. While Sheikh Abdullah agreed not to enter into any relations with any other power without prior consent of the British Government, Percy Zakhariah Cox, the Political Resident in the Gulf, who signed the Treaty on behalf of his government, guaranteed the protection of Qatar ‘from all aggression by sea’. 

On 5 May 1935, Sheikh Abdullah was able to obtain Britain’s approval to protect Qatar from inside and outside-unprovoked attacks. Following British recognition of Sheikh Hamad, the second son of Sheikh Abdullah as the Heir Apparent of Qatar, Sheikh Abdullah signed the first Oil Concession Agreement with the Anglo-Persian Oil Company on 17 May 1935. 

Accordingly, in October 1938, drilling of first well in Qatar began and the discovery of oil was made at Dukhan structure in January 1940. However, the oil wells were capped as the result of the progress of the Second World War. On 30 June 1948, Sheikh Abdullah appointed Sheikh Ali Bin Abdullah Al-Thani as the Deputy Ruler following the death of Sheikh Hamad on 27 May 1948. Sheikh Abdullah’s last act as the Ruler of Qatar was the signing of a Seabed Concession with Central Mining and Investment Corporation Ltd. on 5 August 1949. The Sheikh died on 25 April 1957.