God's War: A New History of the Crusades

In the later eleventh century, holy war became a particular and intimate concern of the reformed papacy, one which was to transform Christian attitudes and practices for half a millennium. The main thrust of papal reform was towards restoring to the church the pristine autonomy and spirituality of the Acts of the Apostles. This required enforcing canonical rules on the secular clergy, prohibiting abuses such as simony (buying or selling a cure of souls), clerical marriage, treating ecclesiastical office as property or political position and the intrusion of lay control over clergy and churches. A radical alteration was projected in the relationship of church and state which, since the Carolingians and perhaps since Constantine, had assumed mutual cooperation rather than separation. This carried severe political risks. At most centres of political power, the church was inextricably linked with secular rule: kings, notably in England or Germany, looked to churchmen for material and political assistance, received their prayers in scarcely disguised king cults and exercised recognized powers of patronage in church appointments. Exclusion of lay control not only undermined powerful and well-established political structures, it cut at local patronage systems whereby donor families maintained close, proprietorial interests in monasteries they had founded or subsidized or in parishes they had established on their estates. For the secular clergy, reform implied a deliberate attempt to distinguish the clerical order from the habits and behaviour of the laity. Crudely, reform aimed at making them more like monks in celibacy, in immunity from the material snares of money and personal property, and in obedience, to canon law, their ecclesiastical superiors and, ultimately, the pope. The social impact was potentially considerable, marking the end of the inheritance of clerical land and office. For the church, while there were clear economic advantages in denying the heritability, division and potential alienation of church property, there remained the argument of law and morality. The impact of papal reform was profound because of such effective combination of the temporal and spiritual.

While moral and institutional reform of the clergy had been promoted in many areas of early eleventh-century western Christendom, the annexation of the papal office by a cosmopolitan group of radicals and puritans from the mid-1040s provided reformers with the oldest, most dignified institution of church government with which to exercise authority and impose doctrinal, legal and liturgical uniformity. The challenges to the reformed papacy became those of politics and discipline as well as law and doctrine. Skilfully, if controversially, manipulating political circumstances in Italy and Germany, the reforming popes asserted not just the independence of the church, libertas ecclesiae, but the autonomous primacy of the see of St Peter. Trumpeting the Petrine texts in the New Testament as demonstrating how Christ gave St Peter – and therefore the pope as his heir or, more telling, vicar (i.e. representative) – rule of the church and authority in heaven and on earth (e.g. Matthew 16:18–19), the reforming popes increasingly claimed authority not just over all churches but over states and laymen as well. Ideologically and politically, this invited opposition, much of it physical. To establish and protect their ‘right order’ of Christendom, successive popes were forced or chose to fight with temporal weapons. The First Crusade was a direct result of this.