The Ottoman invasion and conquest of the Balkans, for example, resulted in Ottoman control of these regions. However, very few of the Ottomans were ethnically Turkish, so the Ottomans who remained in Europe were the same kind of ethnic mixture as obtained in Anatolia. The original Ottoman conquest of Anatolia was made up of something like 30000, in a region with a population of perhaps 4000000, so the Ottomans became largely a military ruling elite, with a population that was essentially of the same ethnicity as existed before the Ottoman conquest, the people being Greeks, Cappadocians etc etc. Similarly, the people of the Balkans remained essentially the same as before the conquest, Greeks, Albanians, Serbs, Croats, Vlachs etc. Some assimilated to Ottoman society and culture more than others, so some adopted Islam, and "turned Turk", others remained Christian. Once the Ottoman Empire in Europe was destroyed, many of the "Turks" were massacred by their Christian neighbours, and many fled to the rump of the Ottoman Empire. These people were culturally "Turks" but not really ethnically. Misha Glenny's book on the Balkans, "Balkans: Nationalism, War and the Great Powers, 1804-1999" goes into this in some detail.