 However, though the Pictish language did not disappear suddenly, a process of Gaelicisation (which may have begun generations earlier) was clearly under way during the reigns of and his successors.By a certain point, probably during the 11th century, all the inhabitants of Alba had become fully Gaelicised Scots, and Pictish identity was forgotten.In 1018, after the conquest of the Lothians by the Kingdom of Scotland, Gaelic reached its social, cultural, political, and geographic zenith.