 Its capital was at Serdica (modern Sofia).Emperor Aurelian (270-275), confronted with the secession of Gallia and Hispania from the empire since 260, with the advance of the Sassanids in Asia, and the devastations that the Carpians and the Goths had created in Moesia and Illyria, abandoned the province of Dacia created by Trajan and withdrew his troops altogether, fixing the Roman frontier at the Danube.A new "Dacia Aureliana" was organised south of the Danube out of central Moesia, with its capital at Serdica.