"The one who fights according to the sense of 'sacred war' is spontaneously beyond every particularism and exists in a spiritual climate which, at any given moment, may very well give rise and life to a supra-national unity of action. This is precisely what occurred in the Crusades when Princes and Dukes of every land gathered in the heroic and sacred enterprise, regardless of their particular utilitarian interests or political divisions, bringing about for the first time a great European unity, true to the common civilisation and to the very principle of the Sacred Roman Empire."