Complex sentence: The abbey and basilica were then renamed in honour of Saint Nazarius: the main church of Saints Peter, Paul, and Nazarius was consecrated by the Archbishop of Mainz in 774, in the presence of Charlemagne.
Split into simpler sentences: The abbey and basilica were then renamed in honour of Saint Nazarius. The main church of Sts Peter, Paul, and Nazarius was consecrated by the Archbishop of Mainz in 774, in the presence of Charlemagne.