This marks the start of Islam, the conversion of the Arabian peninsula, and the splintering of beliefs among Muslims. Umar would later conquer the rest of the Arab world, and much more.
This represents the initial conquering of Byzantine land, and Muslim's first taste of Byzantine Administrative power. Their Conquest of Egypt shows how Arabs would treat other nations they conquered for the next 200 years. This also marks the pint of the spread of Islam to Africa and the east, which would prove pivotal when Europeans attempt to expand their almost 1000 years later.
This was the first probe into Europe conducted by Muslims. Not only did this cause several conflicts, including the Second Crusade, But also was the reason the Spanish and Portuguese viewed colonization as a prolonged Reconquista
Although it is not the first contact with Muslims, the attention of Europe was firmly placed on the Muslim world after the conquest of the Holy Land. The belief of ridding the world of infidels would last up until the Age of Enlightenment, although you can sometimes seen similar beliefs today.
Ibn Battuta demonstrates The ability for Islam to spread in incredible ways. His travels exceed of Marco Polo, showing the versatility and excellent navigational skills of Muslims.
This was the beginning of the push into European lands, and the causes of many wars to follow between European powers and Muslims. This also obliterated the final bastion against the Ottomans.
With the decline of The Ottoman Empire, many European countries were able to colonize portions of Africa that were previously beyond their reach. The French Colonized Algiers in the 1830's, marking the first Muslim people to fall, with the exception of small cities, such as Ceuta.
This was the beginning of the end for The Ottomans. This war was fought over the Orthodox churches under Ottoman Control. Although their were wars before and after, This marks a point of weakness, and colonial powers took advantage.
WW1 was one of the bloodiest conflicts the world had ever seen. The intense fighting in modern day Iraq and Egypt, left the Ottomans almost completely devoid of resources to continue as a nation. European powers finally divided up the Ottoman lands, which began colonialism in the Arab world.
Beginning with the Russian control of the Afghani People, nations have been invading Muslims lands. With colonialism still of their minds, Muslims offer fierce resistance to foreign ways of life, in order to preserve their identity in an ever changing environment.