The European science of history approached divers access to the Crusades since Steven Runcimans monumental narration A History of the Crusades, written from a Byzantine perspective, was published in 1954. The French science of Mediaeval history, led by Jean Richard – Le royaume latin de Jérusalem (1953) respectively L’esprit de la croisade (1969) – gave an outstanding illustration of the high mediaeval phenomenon of universal historical relevance: the decamp of the “Franconia” to “Outremer” for the exoneration of the sanctuaries from the hands of the heterodox. Also the survey of Hans Eberhard Mayer History of the Crusades (Geschichte der Kreuzzüge) documented the historical causation, the main features and carriers of the, in seven Crusades divided, age of Crusaders through versatile evidence such as eyewitness reports or song compositions in this tradition of a dual principle of understanding of notion and fluctuation. From Pope Urban II to the capitulation of Acre, this examination between Orient and Occident, the Arabic-Muslim world with the Christian-European powers is reviewed by the categories of ideal and substantiality. Peter Thorau especially considers the Islamic perspective in his introduction backgrounds, history and implications of the crusades (2004). The Briton Jonathan Riley-Smith selects a multi-perspective access by asking for the concept (The first crusade and the idea of crusading, 1986), the protagonists (The first crusades, 1095-1131, 1997), the reasons (Wars in the name of God/ Kriege im Namen Gottest, 1999) and the interpretation (Why holy wars? Causes and Motives/ Wozu heilige Kriege? Anlässe und Motive, 2003). With his treatise (2003) Nikolas Jaspert gives new impulses of science. He precisely considers the target areas and the process, the postulate, the organisation, the reactions and the results. He disputes the relevancy of the crusades movement, Muslim, heretics and Christians as enemies, the four Christian Crusader dominances until their nemesis and then allocates to the Crusades at the Iberian Peninsula. During the search of cause and catalyst he ends up with the relativisation of assumed aims. He distinguishes between five motivational complexes and evaluates the effectuality of these motives. He also identifies the change of religiousness and measures the dedication of the Kings. Widely included are foreign perception, the Islamic point of view and the interreligious cooperation; the Crusader states in the front Orient, the virtual powers and religious congregations as well as the trade structures of the Mediterranean Sea. Therefore, with a social and culture historical approach, experience is added as a further section to the current science of Crusades. Such a revision is supported by American historians like Christopher Mc Evitt, who use the open term of Crusades as a concept, a metaphor and a myth and continue researching on this (Crusades, crusading and crusader societies, 2010).