The ecclesiastical history of Torres (Turris Lybissonis) goes back to the fourth century.

In 304, the soldier Gavinus, Protus a priest, and the deacon Januarius suffered martyrdom there.

Other bishops include Marinianus, a contemporary of Gregory the Great; Novellus (685), whose ordination caused a controversy between Pope John V and the Archbishop of Cagliari; and Felix (727), who took refuge at Genoa from the Saracens.

Pietro Spano (1422) was a restorer of discipline; under him the episcopal see was definitively transferred to Sassari by Pope Eugenius IV.

This bishop intended to erect a seminary for the training of the clergy, but his death frustrated the plan.