Calvinism is a belief system based upon the teachings of John Calvin, of which the name is derived. Calvinism initially was a denomination founded by John Calvin during the Protestant Reformation, but has spread to other sects, most notably Evangelical circles in recent years, and most prominently in Presbyterianism. Pure "Calvinist Churches" are hard to come by these days, largely being replaced with the Presbyterian Church. Calvinism is the polar opposite of Arminianism and is a form of Monergism. Anyone who is a Calvinist is considered Reformed. Calvinism stresses the sovereighnty of God above all else.