The major political and military event during George I’s reign, a war against the Byzantine Empire, had its roots back to the 990s, when the Georgian prince Curopalate David of Tao, following his abortive rebellion against Emperor Basil II, had to agree to cede his extensive possessions in Tao and the neighbouring lands to the emperor on his death. All the efforts by David’s stepson and George’s father, Bagrat III, to prevent these territories from being annexed to the empire went in vain. Young and ambitious, George launched a campaign to restore the Kuropalates’ succession to Georgia and occupied Tao in 1015–1016. Byzantines were at that time involved in a relentless war with the Bulgarian Empire, limiting their actions to the west. But as soon as Bulgaria was conquered, Basil II led his army against Georgia (1021). An exhausting war lasted for two years, and ended in a decisive Byzantine victory, forcing George to agree to a peace treaty, in which he had not only to abandon his claims to Tao, but to surrender several of his southwestern possessions to Basil, and to give his three-year-old son, Bagrat IV, as hostage.