Along with his brother Geoffrey and his cousins, Abelard and Herman, Robert was constantly in rebellion against his uncle the duke.
They received the aid, financial and military, of Perenos, the Byzantine duke of Durazzo.
On 1 January 1068, Romanus Diogenes was acclaimed emperor in Constantinople and the Greeks transferred their military attention to the Seljuk threat to their east.
In 1071, with Abelard, and in 1078, with his cousin Prince Jordan I of Capua, Robert was in rebellion again.
Robert and his brother and cousins continued in rebellion after the 1079 peace between Jordan and the Guiscard.