Alp Arslan (in Persian script: آلپ ارسلان; c. 1029–1030 – 24 November 1072) was the second sultan of the Great Seljuk Empire, a military commander and ruler who directed the arrival of the Turks from Central Asia into Anatolia and their struggle there. He is renowned for his success at the Battle of Manzikert, fought in 1071 against the Byzantine emperor Romanos Diogenes.
For Alp Arslan's date of birth, Zahir al-Din Nishaburi, al-Husayni al-Yazdi, Mirkhwand, Khwandmir, and Hasan-i Yazdi record 10 January 1030, whereas al-Bundari, Ibn Khallikan, and Ibn al-Adim record 1032–33. The 12th-century historian Ali Ibn al-Athir likewise records 1032–1033, but also mentions 20 January 1029 as an alternative account. Because the date 1032–1033 does not fit chronologically with what is known of Alp Arslan's life, the date of 20 January 1029—transmitted by Ali Ibn al-Athir as an alternative account—is generally accepted in the literature. However, Koç and Şahin argue that using 10 January 1030, the date recorded by many sources, would be far more suitable as Alp Arslan's date of birth than 20 January 1029, which is transmitted only by Ali Ibn al-Athir as an alternative account.
The son of Chaghri Bey, the Governor of Khurasan and one of the founders of the Great Seljuk State, and the nephew of the Seljuk Sultan Tughril Bey, Alp Arslan grew up amid the hard conditions of that state's founding period. Alp Arslan had entered Tughril Bey's service as a child at the Merv Kurultai convened in the aftermath of the Battle of Dandanaqan. In this post, which he held for about three years, he succeeded in becoming a person whose word was heeded even in important and intricate affairs of state.
When his father, the Ruler of Khurasan Chaghri Bey, fell seriously ill in 1043, he returned to Khurasan and was declared heir apparent. Shortly afterward, in the same year, the Ghaznavid army led by Mawdud of Ghazni attacked the region of Tokharistan held by the Seljuks. Alp Arslan, who was then in the city of Balkh, defeated the Ghaznavids. He later also repelled another Ghaznavid attack. The defeated Ghaznavids withdrew, abandoning the places they had seized. He then defeated the Karakhanid ruler Arslan Khan. In recognition of these successes, his father Chaghri Bey declared him protector of the eastern frontier of the Seljuk State.