God's War: A New History of the Crusades

However, Augustine was no warmonger. The world of the spirit was preferable to that of the flesh. Although public prayers, litanies and masses continued to be said from the fifth to the eight centuries, especially under papal instigation in Rome itself, to invoke divine aid in wars against enemies of the church, the Christian tradition of withdrawal from the world, of non-violence and condemnation of temporal aggression remained, if anything strengthened by the spread of monasticism across Christendom. Nonetheless, Augustine had moved the justification of violence from lawbooks to liturgies, from the secular to the religious. His lack of definition in merging holy and just war, extended in a number of later pseudo-Augustinian texts and commentaries, produced a convenient conceptual plasticity that characterized subsequent Christian attitudes to war. The language of the bellum justum often described what came closer to bellum sacrum. This fusion of ideas might conveniently be called religious war, waged for and by the church, sharing features of holy and just war, allowing war to become valid as an expression of Christian vocation second only to monasticism itself.

A just war was not necessarily a holy war, although all holy wars were, to their adherents, just. While holy war depended on God’s will, constituted a religious act, was directed by clergy or divinely sanctioned lay rulers, and offered spiritual rewards, just war formed a legal category justified by secular necessity, conduct and aim, attracting temporal benefits. The fusion of the two became characteristic of later Christian formulations. Where Rome survived, in Byzantium, the coterminous relation of church and state rendered all public war in some sense holy, in defence of religion as well as state, approved by the church, none more so than when the Emperor Heraclius defeated the Persians and returned the True Cross to Jerusalem in 630. However, Byzantine warfare remained a secular activity, for all its divine sanction, never a penitential act of religious votaries.

THE GERMANIC WORLD

The advent of successor kingdoms in what had been the western Roman empire from the fifth century presented the Christian church with cultural as well as political problems. By the eighth century the ruling aristocracies of kingdoms in Italy, Gaul, Spain and the eastern British Isles had almost universally adopted orthodox Roman Christianity without radically altering their social assumptions and belief systems in which, in Carl Erdmann’s words, war provided ‘a form of moral action, a higher type of life than peace’.¹⁰ In this new aesthetic, apparently contradictory of Christian teaching, war provided a raison d’être for political power and social status because, with the collapse of Roman civil institutions, war and its associated fiscal and human structures of plunder, tribute and the comitatus or warband of dependent warriors, provided the basis for economic and social cohesion. The army – exercitus – assumed the role of a central public institution in the medieval west. In the process of converting the new rulers of early medieval Europe the church had no option but to recognize their values, even if it sought to defuse them of exclusively martial connotations by employing the new converts’ language metaphorically, much in the manner of St Paul.