Before the castle It is not exactly known when the hilltop of Qal'at Ja'bar was first fortified. The site was already known as "Dawsar" in pre-Islamic times and was located along a route connecting
Raqqa with the west.
11th century and later Qal'at Dawsar was mentioned in 1040/41 when the
Fatimid governor of Syria
Anushtakin al-Dizbari was on a campaign in the area. At an unspecified point afterward it came into the possession of a certain Ja'bar ibn Sabiq, a member of the tribe of
Banu Numayr or
Banu Qushayr. He was killed there in 1071/72. It developed a reputation for being a haven for Bedouin highwaymen from the two tribes. In 1086 it was conquered by the Seljuks under
Malik-Shah I, who granted it to the
Uqaylid commander of the
Citadel of Aleppo, Salim ibn Malik ibn Badran, as compensation for his surrender of
Aleppo. The castle may have been built by the Numayr, but more likely its construction occurred under Salim. Salim's descendants held the castle almost continuously until the late 12th century, except for a brief occupation by
Crusaders in 1102. In 1146,
Zengi besieged the castle, but he was murdered there by one of his own slaves. In 1168, Qal'at Ja'bar passed into the hands of Zengi's son Nur ad-Din, who undertook major construction works at the castle. Most of what can be seen today dates to this period. The castle was heavily damaged during the
Mongol invasions of Syria. Restoration works were carried out in the 14th century.
Tomb of Suleyman Shah Suleyman Shah, the grandfather of
Osman I (
progenitor of the
Ottoman Empire), reputedly drowned in the
Euphrates near Qal'at Ja'bar, and was buried near the castle. However, it is probable that this story resulted from a confusion between Suleyman Shah, and
Sulayman bin Kutalmish, the founder of the Seljuk
Sultanate of Rûm. It is however not certain whether the actual tomb, known as Mezār-i Türk, related to either of these two rulers. In 1973, in response to the rising water level of the newly created Lake Assad, the reputed
tomb of Suleyman Shah and the associated
exclave were moved to a new location north of Qal'at Ja'bar and the castle itself became Syrian territory. During the
Syrian Civil War,
Islamic State of Iraq and the Levant captured the castle in its
2014 offensive in Syria. The castle grounds were suspected to have been subsequently repurposed by ISIL as a training ground, with tunnels and weapons depots built into the site.
Syrian Democratic Forces captured the site on 6 January 2017 as part of its
Raqqa offensive, seizing it after killing 22 ISIL fighters. ==Architecture==