Sultan Berkyaruq was the fifth sultan of the Seljuk Empire. He was the son and the successor of the great Malik Shah. He was born in 1079/80. He ruled the vast Seljuk empire after the death of his father.
His reign as the Sultan started in 1094 and ended in 1105 when he lost his life only at the age of 25. His rule marks the start of the decline and fragmentation of the Seljuk empire, with elites and other strong groups started to gain power by politicising the race to throne.
The era of Berkyaruq was also marked by internal strife, mainly against other Seljuk princes. Although Sultan Berkyaruq was generally supported by the Nizamiyya but this does not means that the Nizamiyya had a collective policy.
The Nizamiyya were most importantly looking to seek reprisal against Taj al Mulk, who was considered to have been behind Nizam al Mulk’s death. A war took place between the two forces in January 1093 and resulted in the defeat of Mahmud’s supporters and the capture of Taj al Mulk. Fortunately for Berkyaruq this loss didn’t cost much and he survived with out a major loss.
Berkyaruq was worried about his uncle Tutush and unfortunately had to deal with him, who not only invaded the Jazira and western Iran but also seized the city of Ray. He was killed by Berkyaruq’s forces near the same city on 25 February 1095.
Berkyaruq as a result managed to strengthen his rule in western Iran and Iraq, and was also acknowledged as the sultan by the caliph. After that Berkyaruq led an expedition in the east upto Tirmidh, where he ratified the Qarakhanids as the vassal rulers of Transoxiana.
He has also designated Qutb al Din Muhammad as the governor of the Khwarazm which is the region of Central Asia. He remains there for almost seven months in the city of Balkh, and then returned to the west.
The most stiff challenge that Berkyaruq faced during his entire rule was the rebellion of his step brother Muhammad in 1098. The rebellion had been planned and strengthen by Nizam al Mulk’s son Mu’ayyid al Mulk. He had formerly served Berkyaruq before and played a very basic and key role in the defeat of Tutush.
After he was sacked by Berkyaruq, he went to the service of Muhammad who immediately appointed him as his minister. Mu’ayyid al Mulk made full use of his new position under Muhammad to took revenge on his rivals. Muhammad however was unable to defeat his rival after a lot of efforts but empire under Berkyaruq’s rule continued to weaken and by the year 1104 with his treasury worn he was forced to sue for peace.
As a result a treaty was made, which admit Muhammad as the ruler of southern Iraq, northern Iran, the Diyar Bakr, Mosul and Syria, while on the other hand Berkyaruq was embraced as the ruler of the rest of Iran and Baghdad. A year later in 1105 Sultan Berkyaruq died and his authority was vanished and his infant son Malik Shah II succeeded him.