Ahmad Sanjar was the Seljuq ruler of Khorasan from 1097 until in 1118, when he became the Sultan of the Seljuq Empire, which he ruled until his death in 1157.
Early years
Sanjar was born in ca. 1086 in Sinjar, a town situated in the borderland between Syria and the al-Jazira. Although primary sources state that he was named after his birthplace Bosworth notes Sanjar is a Turkic name, denoting "he who pierces", "he who thrusts". He was a son of Malik Shah I and participated in wars of succession against his three brothers and a nephew, namely Mahmud I, Barkiyaruq, Malik Shah II and Muhammad I. In 1096, he was given the province of Khorasan to govern under his brother Muhammad I. Over the next several years Ahmed Sanjar became the ruler of most of Iran with his capital at Nishapur.
Governor of Khorasan
A number of rulers revolted against Sanjar and continued the split of the Great Seljuq Empire that had started upon dynastic wars. In 1102, he repulsed an invasion from Kashgaria, killing Jibrail Arslan Khan near Termez. In 1107, he invaded the domains of the Ghurid ruler Izz al-Din Husayn and captured him, but later released him in return for tribute. Sanjar undertook a campaign to eliminate the Assassins within Persia and successfully drove them from a number of their strongholds including Quhistan and Tabas. However, an anecdote indicates that en route to their stronghold at Alamut, Sanjar woke up one day to find a dagger beside him, pinning a note from Hassan-i Sabbah stating that he would like peace. Sanjar, shocked by this event, sent envoys to Hassan and they both agreed to stay out of each other's way. In 1117, he marched against the GhaznavidSultanArslan-Shah of Ghazna defeating him at Battle of Ghazni and installing Arslan's brother Bahram-Shah in the throne as a Seljuk vassal.
On February 26, 1105 Sultan Barkiyaruq died. He chose his younger son, Muizzeddin Malik-Shah, as heir to the throne. Malikshah took the name Malik-Shah II after being proclaimed the Sultan of the Seljuk Empire. However, the true power was in the hands of his uncle, Muhammad Tapar. In the same year, Muhammad Tapar dethroned his cousin and started to rule the State himself as sultan. When Muhammad died on April 4, 1118, his son Mahmud II was declared as new sultan. When Muhammad's son Mahmud II ascended the throne, Emir or YazdGarshasp II fell into disgrace; slander about him spread to the court that made him lose confidence, and made Mahmud send a military force to Yazd where Garshasp was arrested and jailed in Jibal, while Yazd was granted to the royal cupbearer. Garshasp, however, escaped and returned to Yazd, where he requested protection from Ahmad Sanjar. Garshasp urged Ahmad to invade the domains of Mahmud in Central Iran, and gave him information on how to march to Central Iran, and the ways to combat Mahmud. Ahmad accepted and advanced with an army to the west in 1119, where he together with "five kings" defeated Mahmud at Saveh. The kings who aided Ahmad during the battle were Garshasp himself, the Emir of Sistan and the Khwarazm-Shah, including two other unnamed kings. Nizari forces were also present in Sanjar's army. After being victorious, Ahmad then restored the domains of Garshasp II. Ahmad then marched as far as Baghdad, where he agreed with Mahmud that he should marry one of his daughters, and that he should give up strategic territories in northern Persia. In 1141, Ahmad, along with Garshasp II, marched to confront the Kara Khitan threat and engaged them near Samarkand at the Battle of Qatwan. He suffered an astounding defeat, and Garshasp was killed. Ahmad escaped with only fifteen of his elite horsemen, losing all Seljuq territory east of the Syr Darya. Sanjar’s as well as Seljuks' rule collapsed as a consequence of yet another unexpected defeat, this time at the hands of the Seljuks’ own tribe, in 1153. Sanjar was captured during the battle and held in captivity until 1156. It brought chaos to the Empire - situation later exploited by the victorious Turkmens, whose hordes would overrun Khorasan unopposed, wreaking colossal damage on the province and prestige of Sanjar. Sanjar eventually escaped from captivity in the fall of 1156, but soon died in Merv, in 1157. After his death, Turkic rulers, Turkmen tribal forces, and other secondary powers competed for Khorasan, and after a long period of confrontations, the province was finally conquered by Khwarazmians in the early 1200s.
Death and legacy
Sanjar died in 1157 and was buried in Merv. His tomb was destroyed by the Mongols in 1221, during their invasion of the Khwarezmian Empire. The death of Sanjar meant the end of the Seljuq dynasty as an empire, since they only controlled Iraq and Azerbaijan afterwards. Sanjar is considered the most prominent Sejluq sultan and was the longest reigning Muslim ruler until the Mongols arrived. Although of Turkic origin, Sanjar was highly Iranized, and due to his feats, even became a legendary figure like some of the mythological characters in the Shahnameh. Indeed, medieval sources described Sanjar as having "the majesty of the Khosrows and the glory of the Kayanids". Persian poetry flourished under Sanjar, and his court included some of the greatest Persian poets, such as Mu'izzi, Nizami Aruzi, and Anvari.
Family
Ahmad Sanjar married Turkan Khatun with whom he had two daughterswives of his nephew Mahmud II. After her death, Sanjar married Rusudan, daughter of Demetrius I of Georgia, widow of sultan Masud Temirek. He had no children with her.
