In 235, following the murder of Emperor Alexander Severus in Moguntiacum (modern Mainz), the capital of the Roman province Germania Superior, Maximinus Thrax was acclaimed Emperor. In the following years, there was a growing opposition against Maximinus in the Roman senate and amongst the majority of the population of Rome. In 238 a rebellion broke out in the Africa Province, where Gordian's grandfather and uncle, Gordian I and II, were proclaimed joint emperors. This revolt was suppressed within a month by Cappellianus, governor of Numidia and a loyal supporter of Maximinus Thrax.