In February 1071, Joscelin led a last-ditch effort to relieve the Siege of Bari, which Robert Guiscard had begun in August 1068 after crushing the Apulian rebellion. According to Amatus, Joscelin was carrying lots of gold and other valuables with which to bribe the besiegers. His fleet of twenty ships embarked from Dyrrhachium intending to run the Norman blockade of Bari. Spotted at night by the two lanterns on Joscelin's flagship, it was intercepted by the fleet of Count Roger I of Sicily and defeated in the rare case of a battle at sea fought at night. Joscelin's flagship was captured in the action and another ship was sunk. Amatus records nine vessels captured in total. What was not sunk or captured limped into Bari's harbour. This was the first Norman naval victory in the Mediterranean. According to William of Apulia, "the Norman race had up to this point known nothing of naval warfare. But by thus returning victorious they very much enhanced their leader's confidence..." Following the defeat of the relief squadron, Bari surrendered in April 1071. According to Geoffrey Malaterra, Joscelin was "attired wonderfully in the Greek style" at the time of his capture and thus was he paraded before the besieging troops.