Simplify the following text for a Grade 6 native English-speaking person.
Original: Only Caligula , as the last remaining son of Germanicus , managed to survive the purges of Sejanus , and that he did by moving to Capri with Tiberius in 31 .
Simplified: Only Caligula , the last remaining son of Germanicus , managed to survive the purges of Sejanus . He had moved to Capri to be with Tiberius in 31 .