Before Tiberius, the heirs of Augustus were the sons of Marcus Agrippa, Gaius and Lucius Caesar, whom he adopted and made heir. They advanced through their careers at the same pace and were going to rule together; however, they died young, forcing Augustus to draw another line of succession. In AD 4, Augustus adopted Tiberius on condition that Tiberius adopt Germanicus. This made Tiberius the heir of Augustus, and Germanicus the heir of Tiberius. Like the sons of Agrippa, it was the intention of Augustus that Germanicus and Drusus would rule together.