Tancred of Conversano, the youngest son of Geoffrey, Count of Conversano, became the count of Brindisi on his father's death (sometime after 1085).
Tancred's elder brother Alexander succeeded their father as count of Conversano. In 1121, Count Roger II of Sicily invaded the Basilicata to annex the county of Montescaglioso which had formerly been held by his sister Emma in right of her deceased husband Rudolf Maccabeus. In April, Tancred assisted Duke William II of Apulia and Prince Bohemond II of Taranto and Antioch in conquering the castle of Basento, within the county of Montescaglioso claimed of Roger. With the help of Pope Callistus II, a treaty, however, ended hostilities between the descendants of Tancred of Hauteville. Tancred was recognised as count of Brindisi.
Tancred became part of a grand alliance of rebels, including Robert II of Capua, Ranulf II of Alife, Grimoald of Bari, Geoffrey of Andria, and Roger of Ariano. In the spring of 1129, Roger entered the peninsula with a great army to claim Apulia after William's death (1127). Many of the princes came to heel, but in the summer of 1131, when Roger left, Grimoald and Tancred revolted immediately and took the port of Brindisi and held it against Roger. In May 1132, Grimoald was taken captive and Tancred was only spared by a promise to leave on crusade. He gave up Brindisi for twenty gold coins.