Long before Luther’s hammer rang on the cathedral door, a great reformation (or perhaps, a great revolution) shook the foundations of Christendom. This was the Gregorian Reform of the 11th century. Spearheaded by the imposing, fiery force of Pope Gregory VII and carried out in titanic theological and political struggles with both the State and other catholic bishops, the Gregorian Reform had wide-ranging, lasting effects on the Christian consciousness of Europe. So severe was the shaking, and so fantastic the rebuilding in its wake, that Martin Luther himself once wrote that all the worst features of the papal system during his day could be traced right back to the reign of Pope Gregory VII, five centuries earlier. In a sense, then, significant aspects of the Protestant Reformation, especially its understanding of Christ’s Two Kingdoms, owe their concerns and shape to this earlier catholic reformation.