Modern Hagiography
Lives of the Saints by Alban Butler.
Lives of the Saints by Sabine Baring-Gould.
In A Little Tour in France, Henry James on a visit to Marmoutier tells of cliffside sanctuaries to which Saint Martin and Saint Gatianus retreated for prayer.
Contemporary Hagiography
Gatianus is named by Gregory of Tours in his History of the Franks (as Catianus).
Nihil sub sole novum 