From the third/ninth century onward, Nestorians and Monophysites declined steadily under Muslim rule. The divides between the major Christologies deepened and new fractures appeared. The Chalcedonians divided into the Roman Catholics and Greek Orthodox in 446/1054. Martin Luther’s Protestant Reformation in 923/1517 became another great fissure in the Church, separating Protestants from Catholics. The Protestants grew rapidly in number and, arguing amongst themselves on the finer points of theology, they too divided into dozens of denominations.