[1] He has even been identified with a certain Joscelin de Hareng, who prevented a young Robert Guiscard from physically attacking his elder brother, Count Humphrey of Apulia, during a heated argument in the early 1050s.
[2] On 26 June 1066 in Molfetta, Joscelin and his son-in-law, Amicus, made a donation to the monastery of the Santissima Trinità in Venosa.
[a][1] Besides the port city of Molfetta, he also received from Duke Robert the lordship of Barletta, which had belonged to Count Peter I of Trani until the latter's death (before 1064).
[5] This has traditionally been regarded as the beginning of the first revolt against Robert Guiscard's rule, but it has more recently been argued that the Chronicle mis-dates the events of 1067 to 1064.
[3][6] By early 1068 Duke Robert had defeated the rebels and Joscelin, along with another leader, Roger Toutebove, fled to Constantinople, capital of the Byzantine empire.
[9] 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.
[10][11][12][9] 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.