Historical Religious Pluralism

I've been keeping a stray eye out for historical examples of  temples and churches that have altars and chapels to multiple deities, relating to the vulgar monotheistic-polytheistic thematic mish-mash implied by the world's most popular role-playing game. This one on Redwald is particularly interesting, being from England:

EDWIN was so zealous for the worship of truth, that he likewise persuaded Eorpwald, king of the East Saxons, and son of Redwald, to abandon his idolatrous superstitions, and with his whole province to receive the faith and sacraments of Christ. And indeed his father Redwald had long before been admitted to the sacrament of the Christian faith in Kent, but in vain; for on his return home, he was seduced by his wife and certain perverse teachers, and turned back from the sincerity of the faith; and thus his latter state was worse than the former; so that, like the ancient Samaritans, he seemed at the same time to serve Christ and the gods whom he had served before; and in the same temple he had an altar to sacrifice to Christ, and another small one to offer victims to devils; which temple, Aldwulf, king of that same province, who lived in our time testifies had stood until his time, and that he had seen it when he was a boy. The aforesaid King Redwald was noble by birth, though ignoble in his actions, being the son of Tytilus, whose father was Uuffa, from whom the kings of the East Angles are called Uuffings.

The Venerable Bede, Ecclesiastical History of the English Nation, Book II, Chapter XV