Powers and Thrones: A New History of the Middle Ages

by Dan Jones

Naturally, the actual result of the tetrarchy was protracted civil war; but out of this came Christianity’s big break. In the autumn of a.d. 312, as Constantine was preparing to fight his rival emperor Maxentius at the Milvian Bridge over the river Tiber, he looked to the heavens and saw a blazing cross above the sun, accompanied by the Greek words Εν Τούτω̣ Νίκα (In this sign, conquer). He took this to be a message from the god of the Christians, clearly a god who at that moment appeared to be more interested in battles and politics than in his son Jesus Christ’s program of charity, forgiveness, and reconciliation. In any case, Constantine routed his enemies: Maxentius drowned in the Tiber and was posthumously decapitated. Constantine was now on his way to abolishing the tetrarchy and establishing himself as a single emperor to rule over all. From that moment onward he heaped all the fruits of imperial patronage on Christian bishops and believers.

Crusading—a bastard hybrid of religion and violence, adopted as a vehicle for papal ambition but eventually allowed to run as it pleased, where it pleased, and against whom it pleased, was one of the Middle Ages’ most successful and enduringly poisonous ideas. Its survival is a sign of both its genius and of the readiness of people both then and now to throw themselves into conflict in the name of a higher cause.