Chapter three describes the Feast of the Roman festivals. His first section (55-61) describes the animals brought for sacrifice, and the distribution by the king of food for a great feast. Thus the festivals included sacrifices and shared meals. He sees parallels with this with the Christmas dinner and Pentecost and the year-festivals of the Christian emperors (60).
His major sources are 1- Zosimus Historia Nova (tr. Buchanan and Davis, 1967) 2.1-8. Zosimus was a pagan who believed the coming of Christianity and neglect of the old gods caused Rome to fall. 2- Plutarch “Roman Questions” in Moralia (Loeb, vol. 4).