Drusus Julius Caesar
Gemellus was born the son of Drusus Julius Caesar and Livilla on 10 October AD 19, the same day his uncle Germanicus died in Syria. His paternal grandparents were emperor Tiberius and his wife, Vipsania Agrippina, with his maternal grandparents being general Nero Claudius Drusus and Antonia Minor. He was the twin brother of Tiberius Claudius Caesar Germanicus II Gemellus and the younger brother of his sister Julia. The birth of Gemellus and his twin were celebrated by Tiberius, who claimed that never before in the history of Rome had twins been born to a man as high in rank as Drusus, and the event was commemorated on the reverse of coins. His twin died while still a child in 23.