Complex sentence: After the death of Majorian, Ricimer waited for three months before putting on the imperial throne someone he believed he could manipulate, the senator Libius Severus, who had no distinction but was probably selected to please the Italian senatorial aristocracy.
Split into simpler sentences: After the death of Majorian, Ricimer waited for three months before putting someone on the imperial throne he believed he could manipulate. He finally chose Libius Severus, a senator of no political distinction but was probably selected to please the Italian senatorial aristocracy.