Scripture school
Toward the end of the sixth century Fachtna founded a monastery and school in the area now known as Rosscarbery (Ros Ailithir – “the wooded headland of the pilgrims”). The School of Ross became a celebrated seat of learning and gained an international reputation for study of sacred scripture and learning until the ninth century when it was besieged and destroyed by the Danes. 

Ross diocese
Fachtna is regarded as the first bishop and patron of Ross diocese, which comprises eleven parishes on the seaboard from Timoleague, near Clonakilty, to Aughadown, west of Skibereen, as well as Oileán Cléire and Sherkin Island. Though not listed among the dioceses set up by the Synods of Rathbreasail (1111) or Kells (1152), Pope Celestine III appointed Daniel Bishop of Ross in 1197 and the diocese had its own bishop from the 12th century until 1693, when it was united with Cork and Cloyne. In 1849 the diocese regained its own  bishop, but in 1954 was united with Cork diocese.  

Influence
Fachtna is a favoured name for Catholic boys from the area. There is Catholic church dedicated to St Fachtna in the picturesque village of Glandore. A stained-glass window of St Fachtna by Sarah Purser appears in the Honan Chapel in University College, Cork. A Church of Ireland Cathedral dedicated to him remains in the village of Rosscarbery. His feast is on August 13th.