 Drusus was the youngest son of Livia Drusilla from her marriage to Tiberius Claudius Nero, who was legally declared his father before the couple divorced.Drusus was born between mid-March and mid-April 38 BC, three months after Livia married Augustus on 17 January.Gerhard Radke has proposed the date of March 28 as his most likely birthday, while Lindsay Powell interprets Ovid's "Fasti" as indicating a date of 13 January.