Complex sentence: Paullus joined the political rebel Marcus Junius Brutus the Younger and after Brutus' suicide in 42 BC, Paullus was pardoned and lived his remaining years at Miletus.
Split into simpler sentences: Paullus joined the political rebel Marcus Junius Brutus the Younger. When Brutus died in 42 BC, Paullus was pardoned and lived his remaining years at Miletus.