The name Imola was first used in the 7th century by the Lombards, who applied it to the fortress (the present Castellaccio, the construction of which is attributed to the Lombard Clefi), whence the name passed to the city itself. According to Paul the Deacon, Imola was in 412 the scene of the marriage of Ataulf, King of the Visigoths, to Galla Placidia, daughter of Emperor Theodosius the Great. In the Gothic War (535–552), and after the Lombard invasion, it was held alternately by the Byzantines and barbarians.