Arles became renowned as a cultural and religious centre during the late Roman Empire. It was the birthplace of Favorinus, known as the sceptical philosopher. It was also a key location for Roman Christianity and an important base for the Christianization of Gaul. The city's bishopric was held by a series of outstanding clerics, beginning with Saint Trophimus around 225 and continuing with Saint Honoratus, then Saint Hilarius in the first half of the 5th century. The political tension between the Catholic bishops of Arles and the Visigothic kings is epitomized in the career of the Frankish St. Caesarius, bishop of Arles 503–542. Suspected by the Arian Visigoth Alaric II of conspiring with the Burgundians to turn over the Arelate to Burgundy, he was exiled for a year to Bordeaux in Aquitaine. Political tensions were evident again in 512, when Arles held out against Theodoric the Great. Caesarius was imprisoned and sent to Ravenna to explain his actions before the Ostrogothic king.