Answer
In 209, Geta was proclaimed co-emperor alongside his father, Septimius Severus, and his elder brother, Caracalla. This act marked the beginning of the Severan dynasty's joint rule. Geta remained co-emperor until his untimely death in 211, when he was assassinated at the instigation of his brother Caracalla, ending their power-sharing arrangement and leaving Caracalla as the sole ruler of the Roman Empire.