The consensus among Christians on the use of violence has changed radically since the crusades were fought. The just war theory prevailing for most of the last two centuries—that violence is an evil that can, in certain situations, be condoned as the lesser of evils—is relatively young. Although it has inherited some elements (the criteria of legitimate authority, just cause, right intention) from the older war theory that first evolved around AD 400, it has rejected two premises that underpinned all medieval just wars, including crusades: first, that violence could be employed on behalf of Christ's intentions for mankind and could even be directly authorized by him; and second, that it was a morally neutral force that drew whatever ethical coloring it had from the intentions of the perpetrators.