Tiberius Gemellus (19-38 AD) was the son of Drusus Julius Caesar and Livilla, the last natural grandson of Roman emperor Tiberius at the time of the emperor's death. His name "Gemellus" signified that he was a twin, as his twin brother died at the age of four in 23 AD. In the same year, his father was murdered by Praetorian Guard prefect Lucius Aelius Sejanus, and his mother was put to death for plotting against Tiberius alongside Sejanus. In 33 AD, he was summoned to Capri, where his grandfather had been hiding for the last ten years, and he was made a joint heir of Tiberius alongside his stepbrother Caligula, the adopted grandson of Tiberius. Caligula loved Gemellus as a brother, and he adopted him as his own heir on Tiberius' death. However, in 38 AD he had Gemellus executed in a fit of rage, attempting to make his sister/lover Drusilla have a reaction to this act of cruelty.