"The Protestant Reformation was a major 16th century European movement aimed initially at reforming the beliefs and practices of the Roman Catholic Church. Its religious aspects were supplemented by ambitious political rulers who wanted to extend their power and control at the expense of the Church. The Reformation ended the unity imposed by medieval Christianity and, in the eyes of many historians, signaled the beginning of the modern era. A weakening of the old order was already under way in Northern Europe, as evidenced by the emergence of thriving new cities and a determined middle class.