Complex sentence: Britto is first known from a meeting of the bishops of Gaul in 374 which was held at Valence on the Rhône, at which he avocated that apostate Christians from the persecution under Emperor Julian (361-363) could return to church under certain conditions.
Split into simpler sentences: Britto is first known from a meeting of the bishops of Gaul in 374 which was held at Valence on the Rhône. Here he sat down to ensure that apostate Christians from the persecution under Emperor Julian (361-363) could return to church under certain conditions.