Turks arrived from Central Asia and settled in the Anatolian basin in around the 11th century through the conquest of Seljuk Turks, mixing with the peoples of Anatolia. The region then began to transform from a predominately Greek Christian one to a Turkish Muslim society. Thereafter, the Ottoman Empire came to rule much of the Balkans, the Caucasus, the Middle East (excluding Iran), and North Africa over the course of several centuries, with an advanced army and navy. The Empire lasted until the end of the First World War, when it was defeated by the Allies and partitioned. Following the successful Turkish War of Independence that ended with the Turkish national movement retaking most of the land lost to the Allies, the movement abolished the Ottoman sultanate on 1 November 1922 and proclaimed the Republic of Turkey on 29 October 1923. Not all Ottomans were Muslims and not all Ottoman Muslims were Turks, but by 1923, the majority of people living within the borders of the new Turkish republic identified as Turks.
Article 66 of the Turkish Constitution defines a "Turk" as "anyone who is bound to the Turkish state through the bond of citizenship"; therefore, the legal use of the term "Turkish" as a citizen of Turkey is different from the ethnic definition. However, the majority of the Turkish population are of Turkish ethnicity and are estimated at 70–75 percent.
The ethnonym "Turk" may be first discerned in Herodotus' (c. 484–425 BC) reference to Targitas, first king of the Scythians; furthermore, during the first century AD., Pomponius Mela refers to the "Turcae" in the forests north of the Sea of Azov, and Pliny the Elder lists the "Tyrcae" among the people of the same area. The first definite references to the "Turks" come mainly from Chinese sources in the sixth century. In these sources, "Turk" appears as "Tujue" (Chinese: 突厥; Wade–Giles: T’u-chüe), which referred to the Göktürks. Although "Turk" refers to Turkish people, it may also sometimes refer to the wider language group of Turkic peoples.
In the 19th century, the word Türk only referred to Anatolian villagers. The Ottoman ruling class identified themselves as Ottomans, not usually as Turks. In the late 19th century, as the Ottoman upper classes adopted European ideas of nationalism the term Türk took on a much more positive connotation. The Turkish-speakers of Anatolia were the most loyal supporters of Ottoman rule.
During Ottoman times, the millet system defined communities on a religious basis, and a residue of this remains in that Turkish villagers commonly consider as Turks only those who profess the Sunni faith. Turkish Jews, Christians, or even Alevis may be considered non-Turks. On the other hand, Kurdish followers of the Sunni branch of Islam who live in eastern Anatolia were sometimes considered "Mountain Turks".Article 66 of the Turkish Constitution defines a "Turk" as anyone who is "bound to the Turkish state through the bond of citizenship." It is believed by Robert Fisk that circa two million Turks may have an Armenian grandmother.