 In 49 AD , Claudius married a fourth time , to <unk> 's mother <unk> , despite her being his niece . To aid Claudius politically , young <unk> was adopted in 50 and took the name <unk> Claudius Caesar <unk> <unk> ( see adoption in Rome ) . <unk> was older than his <unk> <unk> , and thus became heir to the throne . 
