Publius Acilius Attianus (1st – 2nd century AD) was a powerful Roman official who played a significant though obscure role in the transfer of the imperial power from Trajan to Hadrian. He was born in Italica, Hispania Baetica, which was also the birthplace of Publius Aelius Hadrianus Afer, the emperor Hadrian’s father. When Afer died about 86, Attianus and the future Emperor Trajan (another native of Italica) became the ten-year-old Hadrian’s guardians. Otherwise nothing is known of Attianus’s early career, but towards the end of Trajan’s reign he was joint Praetorian Prefect with Servius Sulpicius Similis for colleague. While Similis remained at Rome, Attianus accompanied the Emperor on campaign in the East.