although cleopatra had rejected her 11-year-old brother as a joint ruler in 51 bc, ptolemy xiii still retained strong allies, notably potheinos, his tutor and administrator of his properties. the romans, including caesar, initially viewed him as the power behind the throne. others involved in the cabal against cleopatra included achillas, a prominent military commander, and theodotus of chios, another tutor of ptolemy xiii. cleopatra seems to have attempted a short-lived alliance with her brother ptolemy xiv, but by the autumn of 50 bc ptolemy xiii had the upper hand in their conflict and began signing documents with his name before that of his sister, followed by the establishment of his first regnal date in 49 bc.