Young and ambitious, George I launched a campaign to restore the David Kuropalates’ succession to Georgia and occupied Tao in 1015–1016. He also entered in an alliance with the Fatimid Caliph of Egypt, Al-Hakim (996–1021), that put Basil in a difficult situation, forcing him to refrain from an acute response to George's offensive. Beyond that, the Byzantines were at that time involved in a relentless war with the Bulgar Empire, limiting their actions to the west. But as soon as Bulgaria was conquered in 1018, and Al-Hakim was no longer alive, Basil led his army against Georgia. After a failed first attempt, preparations for a larger-scale campaign against the Kingdom of Georgia were set in train, beginning with the re-fortification of Theodosiopolis. In the autumn of 1021 Basil, at the head of a large army reinforced by the Varangian Guards, attacked the Georgians and their Armenian allies, recovering Phasiane and pushing on beyond the frontiers of Tao into inner Georgia. King George burned the city of Oltisi to keep it out of the enemy's hands and retreated to Kola. A bloody battle was fought near the village Shirimni at the Lake Palakazio (now Çildir, Turkey) on September 11 and the emperor won a costly victory, forcing George I to retreat northwards into his kingdom. Plundering the country on his way, Basil withdrew to winter at Trebizond.