Despite a slight decrease in the number of refugees arriving to Europe after an agreement between the EU and Turkey, the migration crisis is far from over. According to the head of European diplomacy F. Mogherini, in the territory of Libya, there are more than 500 thousand people, who are ready for migration to Europe. The massive arrival of migrants on the continent increases tensions between EU members, threatening the socio-economic development of those countries where refugees predominantly go. Another important direction of the impact of the migration crisis is the new "offensive" of Islam on Europe, since more than 80% of refugees are Muslims, which greatly enhances the influence of local Islamic diasporas. As a result, the question about possible consequences of Muslim migration to Europe appears.
To answer this question let us go back in history. Repeated attempts by Muslims to penetrate into Europe by aggressive means were observed from the 8th to 10th centuries, and then from the 14th to the 18th century. In Western historiography this were seen as a duel between the cross and the crescent, although they had geopolitical and not religious reasons. In turn, under the pretext of protecting the Christian church, the Vatican and the European aristocracy carried out a series of crusades to the Middle East. Jerusalem and the Holy Land were freed from Muslims, although later they again went under Muslims control. These wars were accompanied by anti-Islamic propaganda. The religion of Muslims was presented to Europe as unrighteous and evil faith, and Saracens as "servants of the devil", which had a tangible impact on European public opinion of the time. Even now, many people in Europe are still poorly informed about the religious, domestic and cultural features of the Islamic world.
Muslims arriving in Europe to avoid death in areas of armed conflict, in search of work and better living conditions, have their own religious identity and self-awareness. The experience of migrants of the first and second waves, who came from the Arab Maghreb and Turkey, showed that the integration of Muslims into the European community did not happen. The policy of assimilation has yielded results only in domain of foreign languages learning, and this has not happened in the religious and related cultural and everyday spheres.
 Muslims in Europe. A Report on 11 EU Cities [Electronic source]. Access mode: https://www.opensocietyfoundations.org/sites/default/files/a-muslims-europe-20110214_0.pdf 
 “History of Islamic Militant Attacks in Europe”, The Telegraph, July 22, 2011 
 Perspectives of Otherness: Muslims in Europe between Assimilation and Polarization. European Forum At The Hebrew University Helmut Kohl Institute For European Studies [Electronic source]. Access mode: http://ef.huji.ac.il/sites/default/files/europe/files/shiri_relevy_for_web.pdf 
According to the analysis, the words-patterns of violence in the Koran and in the New Testament are approximately the same number – 2.1% and 2.8% respectively (in Koran even less). But the Old Testament is twice as aggressive as the holy book of Muslims – It contains 5.3% of references to murders and destruction. Anderson also laid out the Bible and the Qur'an on a scale of 8 psychologically accepted emotions. It turned out that there is more anger in the Bible, and in the Qur'an, the themes of fear and faith itself are much more revealed. In conclusion, Anderson summarizes that the Qur'an cannot be considered as more aggressive book than the Bible.
So, although there will be definitely some changes in the European religious map in the near future, it does not mean that Islam as religion can cause some troubles to the Europeans since everybody respects right of others.
 'Violence more common' in Bible than Quran, text analysis reveals [Electronic source]. Access mode: http://www.independent.co.uk/arts-entertainment/books/violence-more-common-in-bible-than-quran-text-analysis-reveals-a6863381.html