Oliver Cromwell was the guy that ran the british civil war where they killed the king, massacred lots of innocent irish, and scots, and confiscated all land belonging to Catholics and Episcipaleans.
Because of the latter mentioned thing, many of the episcipalean Lords went to America and their descendants were the founding fathers of USA. This is why they added and emphasized the bit about freedom of religion in the Constitution/Bill of rights. However, as we now know, the British civil war was not a war between protestants and catholics/episcopeleans, but a means to lift the ban on Jews and allow them to return to England. Of course hindsight is 20/20, but the founding fathers should have focused on the real cause of their ancestor's war.