Ahmad Sanjar
The Seljuk ruler Abu’l-Harith Ahmad Sanjar ibn Malik-Shah, or Ahmad Sanjar, (b. 1085 – d. 1157) had a reign that lasted 40 years, and he ruled over eastern Persia at Merv (now in modern Turkmenistan). After wars of succession, Sanjar ascended to the throne at the age of 10 or 12, nominated and appointed by his half-brother Berk-Yaruq. Early in his reign, he defeated several uprisings and invasions such as those of the Ghaznavids in 1097 and Türkmen in 1098. However, he faced his first defeat at Qatwān in 1141 against the Qara Khitai, also known as the Western Liao Empire.