The Protestant Reformation was a holocaust of art in many parts of Europe. Although Lutheranism was prepared to live with much existing Catholic art so long as it did not become a focus of devotion, the more radical views of Calvin, Zwingli and others saw public religious images of any sort as idolatry, and art was systematically destroyed in areas where their followers held sway. This destructive process continued until the mid-17th century, as religious wars brought periods of iconoclast Protestant control over much of the continent.