The logical successor (and Tiberius' own choice) was his 24-year-old grandnephew, Gaius, better known as "Caligula" ("little boots"). Caligula was a son of Germanicus and Agrippina the Elder. His paternal grandparents were Nero Claudius Drusus and Antonia Minor, and his maternal grandparents were Marcus Vipsanius Agrippa and Julia the Elder.