Tithing to the Church of England was mandatory in colonial America. The Head of The Church of England was The King…then at some point appointed somebody else for appearances, but was essentially still the head of it….
So, if you wanted to support your own church, you were obligated to two congregations:
Theirs & Yours.
"Separation" of Church & State sought to eliminate the obligatory tax to an entity that guides the soul not governs the physical.