Selim I (Ottoman Turkish: سليم الأول; Turkish: I. Selim; 10 October 1470 – 22 September 1520), also known as Selim the Grim or Selim the Resolute (Turkish: Yavuz Sultan Selim), was the sultan of the Ottoman Empire from 1512 to 1520. Despite lasting only eight years, his reign is notable for the enormous expansion of the Empire, particularly his conquest between 1516 and 1517 of the entire Mamluk Sultanate of Egypt, which included all of the Levant, Hejaz, Tihamah and Egypt itself. On the eve of his death in 1520, the Ottoman Empire spanned about 3.4 million km² (1.3 million sq mi), having grown by seventy percent during Selim's reign.

Selim's conquest of the Middle Eastern heartlands of the Muslim world, and particularly his assumption of the role of guardian of the pilgrimage routes to Mecca and Medina, established the Ottoman Empire as the pre-eminent Muslim state. His conquests dramatically shifted the empire's geographical and cultural center of gravity away from the Balkans and toward the Middle East. By the eighteenth century, Selim's conquest of the Mamluk Sultanate had come to be romanticized as the moment when the Ottomans seized leadership over the rest of the Muslim world, and consequently Selim is popularly remembered as the first legitimate Ottoman Caliph, although stories of an official transfer of the caliphal office from the Mamluk Abbasid dynasty to the Ottomans were a later invention.

Selim was born in Amasya on 10 October 1470 as the son of Şehzade Bayezid (later Bayezid II) during the reign of his grandfather Mehmed II. His mother was Ayşe Gülbahar Hatun, a Pontic Greek concubine, formerly confused with Ayşe Hatun, another consort of Bayezid and daughter of Alaüddevle Bozkurt Bey, the eleventh ruler of the Dulkadirids. In 1479 at the age of nine, he was sent by his grandfather to Istanbul to be circumcised along with his brothers. In 1481, his grandfather Mehmed II died and his father became Sultan Bayezid II. Six years later in 1487, he was sent by his father to Trabzon to serve there as governor.

Shah Ismail's brother Ibrahim marched on Trabzon, which belonged to the Ottomans, with an army of 3,000 in 1505. Thereupon, Selim went on an expedition against Ibrahim. With 450 soldiers under the command of Selim, he repelled the army of 3,000 under the command of Ibrahim and chased the Safavids to Erzincan.^{[page needed]} As a result of this expedition, Shah Ismail complained about Selim to Sultan Bayezid II, but he did not get any results.^{[page needed]}

In 1507, the Safavids under the command of Shah Ismail organized an expedition against Ala al-Dawla Bozkurt of Dulkadir. During this expedition, Shah Ismail, who had crossed into Ottoman territory without permission, also included Turkmen warriors who were Ottoman subjects in his army. These actions of Shah Ismail were a violation of Ottoman sovereignty. Bayezid II did not respond to these violations, but Selim, the governor of Trabzon at the time, attacked Erzincan and Bayburt, which belonged to the Safavids, and defeated the 10,000 men Safavid army sent by Shah Ismail in Erzincan.

After Selim's last actions, Shah Ismail sent an army to Trabzon again in 1510. This army, under the command of Shah Ismail's brother, marched to Trabzon. However, Selim, who was in Trabzon, defeated the Safavids.^{[page needed]}

In 1507 Selim successfully defeated the Safavid army at Erzincan. The following year, in 1508, he organised an attack against Georgia. He invaded and captured western Georgia bringing Imereti and Guria under Ottoman rule. During his campaign he enslaved a large number of women, girls and boys, reportedly more than 10,000 Georgians.

As a result of the struggle for the throne that Selim started against his father, Sultan Bayezid II, in 1512, a battle was fought between the parties near Tekirdag. Selim lost the battle.