The city is well known during the 4th century as a center of Christian activity (see also below), due to frequent imperial visits, and through the letters of the pagan scholar Libanius. Bishop Marcellus of Ancyra and Basil of Ancyra were active in the theological controversies of their day, and the city was the site of no less than three church synods in 314, 358 and 375, the latter two in favor of Arianism.