法国著名学者亨利·德卡斯特里伯爵在1896年出版的《伊斯兰教》一书中写道：

One of the French learned writers Count Henri Decastri wrote in his book entitled ‘Islam’ in 1896,

“我无法想象,穆斯林若听到中世纪的那些故事,并明白当时的基督教演说家在颂歌中究竟说了些什么,他们会作何感想。我们所有的颂歌,甚至包括十二世纪以前产生的那些,都源于同一种观念,而这种观念正是十字军东征的根源。这些颂歌充满了对穆斯林的仇恨,其原因在于人们对他们的宗教完全无知。由于这些颂歌和歌曲,对该宗教的憎恶牢牢固定在人们的心中,错误的观念根深蒂固,其中一些至今仍在流传。当时人人都视穆斯林为多神论者、不信道者、拜偶像者和叛教者。”

“I cannot imagine what the Muslims would say if they heard the tales of the mediaeval ages and understood what the Christian orators used to say in their hymns; all our hymns even those which emerged before the 12th century emanated from one concept which was the cause of the crusades, these hymns were filled with hatred towards the Muslims due to the total ignorance of their religion. As a result of those hymns and songs, hatred against that religion became fixed in people’s minds, and the erroneous ideas deeply rooted, some of which are still carried nowadays. Everyone used to regard the Muslims as polytheists, disbelievers, idol worshippers and apostates.”.

这就是欧洲基督教神职人员描述穆斯林及其宗教的方式。中世纪的种种指控极其可怖，它们被用来煽动对穆斯林的仇恨与敌意。基督教世界因此受到影响，十字军东征由此爆发。这场持续了两个世纪的战争，以基督徒的失败和屈辱告终。到了15世纪，当伊斯兰国进入君士坦丁堡时，穆斯林开始重新征服西方。随后在16世纪，穆斯林横扫欧洲南部和东部，把伊斯兰教传播给当地各族人民。在这一过程中，阿尔巴尼亚、南斯拉夫、保加利亚等国的数百万居民皈依了伊斯兰教。十字军式的敌意再度被唤起，东方学的观念也随之兴起。当时的东方学主要关注如何抵抗穆斯林军队、遏止伊斯兰的征服，并减轻穆斯林带来的威胁。