The city became the capital of the Mossi Empire in 1441 and became the permanent residence of the Mossi emperors (Moro-Naba) in 1681. The Moro-Naba Ceremony is still performed every Friday by the Moro-Naba and his court. In 1919 the French made Ouagadougou the capital of the Upper Volta territory (basically the same area as contemporary Burkina Faso). In 1954 the railroad line from Ivory Coast reached the city. Ouagadougou's population doubled from 1954 to 1960 and has been doubling about every ten years since.