The Sacramental Mechanism and the Prohibition of Violence
In The Elementary Forms of the Religious Life Durkheim ( 1995) recognized that certain places and certain times are consecrated (designated as 'sacred') and therefore radically opposed to all that which is profane. Since, by definition, 'elementary' religion has no division of labour by which consecrated persons would be consecrated except only temporarily. Insofar as we are talking about medieval Europe, however, with a well-established division of religious labour, we need also to talk about consecrated persons, in addition to places and times.
There is a more fundamental difficulty with Durkheim's conception of sacred and profane, at least as it applies to the sacramental delimitation of violence. That is, while in Durkheim's conception, the sacred may change (some things may become sacred that were previously profane and vice versa), or simply grow, the distinction between sacred and profane is nonetheless absolute ( 1995: 34ff.). What we find by looking at the delimitation of violence by the sacramental mechanism is that it distinguished sacredness by matter of degree. This is important, because it allows for the gradual expansion of persons, places and times in which violence is prohibited by the sacramental mechanism; it thereby provides increasing pressure towards civilized dispositions in tangent with the increasing royal monopolization of the use of force.
It is worth considering at this point one of the most famous examples of medieval violence with respect to the sacramental mechanism and its violation. In the five more or less eyewitness accounts of the murder of Thomas Becket (as well as in later hagiographies), we find repeated references to the seriousness of the crime committed by four of King Henry's knights, not just as an act of murder, but because of the way that it violated the sacred. The sinfulness of the murder was 'compounded' by 'violating a sacred trinity of time, space and body' (Hayes 2004: 198). This was not only the murder of a consecrated priest, but the anointed Archbishop of Canterbury. This was not only a murder within a church, but the most important cathedral in the land. The violation of the sacred could only have been made worse by measure of time: the violence took place at a side altar in the north aisle, and not at the main altar, and during the Octave of Christmas (29 December 1070), not during the Easter season (Barlow 1986).
The violation of the sacred had the paradoxical effect of 'polluting' (or profaning) the cathedral, and also increasing the sacredness of the corpse of Thomas Becket. Sacraments were suspended at the cathedral for the better part of a year until the cathedral could be reconciled; at the same time, the late archbishop, who, during his lifetime was a somewhat unlikely candidate for beatification, had quite spontaneously been sainted by the people, with only slow and reluctant acquiescence from his own monks, and the belatedly approval of the Pope (Barlow 1986). Becket's remains and the site of his murder quickly became one of the most popular pilgrimage destinations in Europe.
Sometimes, as in the case of Becket, the saints are made holier by suffering violence and martyrdom. There was a long-standing prohibition (even when it was observed in the breech) against consecrated persons committing acts of violence and warfare. When the bishops and Peace Councils stepped into the Carolingian defenders of the church's shoes, they affirmed what had long been an implicit rule; the steps that they took to reinforce it set into motion a new set of dynamics. The Peace Councils' initial concern was to 'set apart' consecrated persons from acts of violence, and to protect the sacred with anathemas, and by extracting vows sworn in the presence of relics of the saints (themselves often sanctified by violence).
The peasantry were initially protected from violence since they fell under the care and responsibility of the bishops, along with their livestock, a sort of contagion of the sacred that did not quite provide quite the same protection as religious orders. The peasants are included from the very beginning of the Peace Councils, but typically without much by way of rationalization beyond their bishops' protection, and their status as unarmed persons. From the Council of Narbonne (1054), however, the category of sacred person comes to include all Christians, including not only the peasants, but also the warrior class itself (Head and Landes 1992: 8). This is not to say that all Christians become of equivalent sacredness, and indeed violent offences against the clergy continue to be taken as much more serious offences than violence against lay persons - there is a degree of sacredness conferred on each, but they are considered quite distinct from the Saracen, the pagan or the heretic, against whom violence becomes not only licit but an act of piety.
The early Peace Councils clearly identify monasteries and churches as institutions to be preserved from violence, or against whom violence may not be directed, including buildings, property and people. Rituals of consecration designate them as such, and should violence occur in the sacred space, the celebration of the Eucharist would be suspended until the building could be cleaned of its pollution by means of a ritual of reconciliation - effectively needing to be re-consecrated. The occurrence of violence in sacred space had the capacity to pollute and render it unfit for the celebration of the Eucharist. Given the importance of the Eucharist for medieval Christian spirituality, extensive efforts were taken to prevent people from exercising violence in sacred space. Daniel Thiery tells an amusing story about two men who get into a fight in the parish church, end up assaulting and bloodying the priest who warns them against committing violence in the church; thereafter they try to force him to continue to say the Mass, so as to un-pollute (or prove that they have not polluted) the parish church, and to thereby escape the social consequences that their violation would inevitably entail (Thiery 2009).
The parish church was one of the few indoor public spaces in most medieval communities. However, sanctuary from violence did not end at the door to the church. Varying degrees of sacredness surround the church, certainly encompassing the graveyard and perhaps also a perimeter of up to 50 meters, including the buildings nearby. Abbeys and cathedrals might have a larger surrounding area designated as free from violence. Durham Cathedral, which had a charter of sanctuary making it a place of refuge from the law (though with conditions), had a zone of sanctuary that extended a mile from the cathedral doors. Within the building, not all spaces are equally sacred. Thus, the porch, where relatively secular business could be conducted, disputes settled and marriage contracts made, is considered less sacred than the nave. This was in turn marked off from the quire and presbytery as less sacred space.
The first declaration of the Truce of God a the Council of Toulouges (1027) was designed to protect the Sabbath from being desecrated by violence and hence extended from Saturday night to Sunday morning, offering some hours that insulated the Sabbath on either side. Through the 1030s and 1040s, the days of the Truce tended to expand, not just to other days of the week, but to other high days and holy days, including a significant season at Christmas and Easter. The Council of Narbonne (1054) made violence and warfare licit on just 80 days out of the calendar year (Cowdrey 1970).
In short, in the period from the Peace Councils through the Middle Ages, we find increasing areas consecrated and (at least in designation) free from violence, an expansion of consecrated time, and an increasing range of people against whom violence ought not to be directed by virtue of their sacred protection. Violence is increasingly constrained by the threat of excommunication, anathema and the consequences of polluted religious space. The sacramental mechanism determines where, when and against whom violence may be legitimately directed without profaning those who commit the violence, or the space in which it is committed.
-  I have often thought it should be noted, but have not seen anyone do so, that both of these seasons tend to fall outside the summer months, which were much preferred for long distance travel and warfare, as roads were passable, and fields provided sufficient grazing for the many horses a military action entailed.