Celtic religion was probably similar to ancient shamanic beliefs that everything has a soul: celestial bodies, mountains, moors, rivers, plants, animals and humans. And so alongside their tribal deities and mother goddesses, the Celts also worshipped natural phenomena. Animals were thought to be divine or the manifestation of a god or goddess. Certain objects and symbols had magic powers.
Although tribes which became part of the Roman Empire had to make offerings to Roman gods, they were still allowed to practise their own religions. Only if tribes fought against Roman rule were they persecuted for their religious beliefs. The Romans considered it particularly important to venerate the emperor and members of his family. Everybody had to participate in those special festivals.