4. Celtic and Roman deities combined rather well in Britain
The Roman conquest of Britain saw the Druids driven out and the sacred groves cut down. However, surprisingly, the Mediterranean invaders were happy to tolerate the Celtic gods. In general, the Romans had no problem with the deities of the lands they conquered- as long as they did not become a focal point for resistance. So it was Roman policy to allow their conquered people to continue worshipping as they pleased. In some cases, these native and Roman deities combine cults.
One such example of this occurred on the lands of the Dobunni tribe in southwest England, at a hot spring sacred to the Celtic water goddess Sulis. After the invasion of 43AD, the Romans quickly occupied the Dobunni tribal lands. Sulis’s spring just happened to lie along the River Avon, a vital waterway and the Romans were quick to establish a fort there. The hot springs were a desirable feature to the bath loving Romans. However, they were too respectful of the sanctuary of Sulis to appropriate it and kick the goddess out.
Instead, they decided to embellish Sulis’s existing native sanctuary with a magnificent new temple and bathhouse. They rededicated the new shrine to Sulis in partnership with the Roman goddess Minerva. The Roman’s reconciled the locals to the addition of their own deity by claiming the two goddesses were the same. And so Sulis became Sulis Minerva and around her sanctuary grew up the town of Aquae Sulis, which today is better known as Bath.