Pan-Arabism or Arabism is an ideology espousing the unification of the countries of North Africa and West Asia from the Atlantic Ocean to the Arabian Sea, referred to as the Arab world. It is closely connected to Arab nationalism, which asserts that the Arabs constitute a single nation. Its popularity was at its height during the 1950s and 1960s. Advocates of pan-Arabism have often espoused socialist principles and strongly opposed Western political involvement in the Arab world. It also sought to empower Arab states from outside forces by forming alliances and – to a lesser extent – economic co-operation.
The origins of pan-Arabism are often attributed to Jurji Zaydan and his Nahda (Revival) movement. Zaydan had critical influence on acceptance of a modernized version of the Quranic Arabic language (Modern Standard Arabic) as the universal written and official language throughout the Arab world, instead of adoption of local dialects in the various countries. He also popularized through his historical novels certain heroes from Arab history. Pan-Arabism was first pressed by Sharif Hussein ibn Ali, the Sharif of Mecca, who sought independence for the Mashreq Arabs from the Ottoman Empire, and the establishment of a unified Arab state in the Mashreq. In 1915 and 1916, the Hussein-McMahon Correspondence resulted in an agreement between the United Kingdom and the Sharif that if the Mashreq Arabs revolted successfully against the Ottomans, the United Kingdom would support claims for Mashreq Arab independence. In 1916, however, the Sykes-Picot Agreement between the United Kingdom and France determined that parts of the Mashreq would be divided between those powers rather than forming part of an independent Arab state. When the Ottoman Empire surrendered in 1918, the United Kingdom refused to keep to the letter of its arrangements with Hussein, and the two nations assumed guardianship of Mesapotamia, Lebanon, Palestine and what became modern Syria. Ultimately, Hussein became King of only Hijaz, in the then less strategically valuable south, but lost his Caliphate throne when the kingdom was sacked by the Najdi Ikhwan forces of the Saudites and forcefully incorporated into the newly created Kingdom of Saudi Arabia.