In 44 BC, ten years after the conquest of Gaul, Julius Caesar was assassinated and civil war erupted. According to the historian Cassius Dio, in 43 BC, the Roman Senate ordered Munatius Plancus and Lepidus, governors of central and Transalpine Gaul respectively, to found a city for a group of Roman refugees who had been expelled from Vienne (a town about to the south) by the Allobroges and were encamped at the confluence of the Saône and Rhône rivers. Dio Cassius says this was to keep them from joining Mark Antony and bringing their armies into the developing conflict. Epigraphic evidence suggests Munatius Plancus was the principal founder of Lugdunum.