Following Augustus' ascension as the first emperor of the Roman Empire in 27 BC, his family became a de facto royal house, known in historiography as the "Julio-Claudian dynasty".
Tiberius (Tiberius Caesar Divi Augusti Filius Augustus), a Claudian by birth, became Augustus' stepson after the latter's marriage to Livia, who divorced Tiberius' natural father in the process.