Gatianus in the third century AD was the founding bishop of the see of Tours. He was one of the "seven apostles of Gaul" commissioned by Pope Fabian to evangelize in the region.

The Archdiocese of Tours is a Latin Church archdiocese of the Catholic Church in France. The archdiocese has roots that go back to the 3rd century, while the formal erection of the diocese dates from the 5th century.