Isn't the idea of a secular government pretty recent? So you're saying that religion had no part in religious inspired violence throughout history? Really?
No secular governments have always existed. The Greeks and Rome had secular governments. Kings ruled independent of the church, and it was a power conflict between the kings and the church that lead to the Protestant Reformation Movement. However, I think the most distance between church and state was created in the US first. England broke from the church and created its own church. A main cause of the American Revolution was fear that the king of England would impose his church on everyone in the colonies. The colonies in the north were started by people who thought they had the best understanding of religion, and they competed with each other to produce the most saints. We did not exactly have freedom of religion then, but established it, in part, because the different religious colonies were fighting each other. They had peace only if they could completely avoid each other. As soon as they grew big enough to have a problem avoiding each other they began fighting. The constitution created a secular government over all of them to end the fighting over many things, from charging a toll to use a road, to differences in religious beliefs. The US constitution did what Wellwisher said, gave us a team leader.