Najd Sanjak an autonomous separate country within the empire. The sultan recognized Abdullah II Al-Sabah as the kaymakam of Kuwait as a subprovince of al-Ahsa, formally acknowledging that Kuwait was a part of the Ottoman Empire and that it was ruled by the Sabah family. In 1913 Ibn Saud launched an attack on Hofuf, where 1,200 Turkish troops had been stationed since the province's annexation in 1870. The Ottoman garrison was expelled from Hasa, and the territory fell to the Al Saud. Even after the conquest of Hasa, Britain considered Ibn Saud to be an Ottoman vassal, and the Anglo-Ottoman Convention of
Transformation of the Ottoman Empire military ventures could occasionally lead to escalation, as in 1592-3 when the Long War was provoked by the Ottoman governor of Bosnia's conquest of Bihać. In contrast with their Hungarian and Safavid frontiers, the Ottomans generally did not seek to expand further north from the Black Sea, being concerned primarily with its defense and the security of its sea lanes. The Ottomans maintained a series of fortresses along the Black Sea's northern shore, in the territory of modern Ukraine. Major sites were located in Akkerman, Özü, and Azak. Also of critical importance for the northern frontier was the Ottoman vassal