Actually yes, they did. Emperor Constantine, perhaps you've heard of him?
Religion doesn't belong in the schools... your children have the remaining 16 hours of the days on the week followed by 48 hours on the weekends to practice their religion. Say what you want about the moment of silence and FCA, but really thats about the extent of religious practice/recognition that should be allowed in schools.
Give unto Caesar what is Caesar's, and give unto god what is god's. Or something like that.