The First Crusade defined the Middle Ages. It established a common identity for European chivalry, firmly rooting it in the Christian faith. It influenced behavior, with devotion and service emerging as much-desired personal qualities, being extolled in verse, prose, song, and art. He idealized the concept of the devout knight who fights in the name of God. The pope became a leader not only of great spiritual significance but also of paramount political importance. He gave a common goal to the western principalities, creating a structure in which the defense of the Church, more than desirable, was an obligation. From the First Crusade came the ideas and structures that shaped Europe until the Reformation.