Capitals: Eflani, Kastamonu, Sinop
Official Language: Turkish
Established: 1292 AD/CE
Disestablished: 1461 AD/CE
The Seljuq Sultan Masud II gave Kastamonu to Temür Yaman Jandar, a commander from the sultan's candar corps, in thanks for rescuing him from Mongol captivity. This province, however, was already under the control of the Chobanids. Following Temür's death, his son Süleyman I conquered the province and annexed Safranbolu and Sinop, formerly ruled by the descendants of Mu‘in al-Din Suleyman. Süleyman then appointed his son Ibrahim I as governor to Sinop and a second son Ali to Safranbolu. Süleyman reigned under the authority of the Ilkhanate, the Mongols of Persia, until the death of the ruler Abu Sa'id.
Following the death of Süleyman I, his sons Ibrahim I and Ali fought for the throne. In 1339 Ibrahim was victorious and took over the rule of Kastamonu. Upon his death, his cousin Adil replaced him (1346–1361). When Adil died, his son Kötürüm Bayezid became bey. Bayezid fought twice with Kadi Burhan al-Din, the ruler of the Sivas region, and in 1383 lost Kastamonu to one of his own sons, Süleyman II, who received military support from the Ottoman sultan Murad I. Bayezid left for Sinop, and thus the Jandarid Principality was divided. After Bayezid's death in 1385, his son Isfendiyar succeeded him.
Based in Kastamonu, Süleyman II remained faithful to Murad I, his supporter in his revolt against his father, and participated in Ottoman campaigns in Europe in 1386 and 1389. Murad's successor, the aggressive Beyazid I launched an assault in 1391 on Kastamonu as part of an effort to control the Anatolian beyliks. Süleyman II was killed and Jandarids' rule in Kastamonu ended.
Meanwhile, fearing conflict with the powerful Ottomans, Isfendiyar requested immunity from Beyazid in return for being subject to Ottoman reign. Beyazid granted Isfendiyar an autonomy. Following the sultan's defeat by the Mongols in 1402, Isfendiyar recognized the authority of the Mongol khan Timur, who confirmed him in the traditional Jandarids' lands of Kastamonu, Kalecik, Tosya, and Çankırı.
After Timur left Anatolia, during the Ottoman Interregnum, Isfendiyar stood close to all the four sons of Beyazid avoiding any conflict. When one of his sons, Kasım claimed control over Çankırı and Tosya, and declared the annexation of these areas to the Ottoman Empire, the Jandarids' dominion was divided once more. But Isfendiyar revolted against the new sultan Murad II, only to be defeated, and retreated to Sinop (1423). Isfendiyar died in 1439, to be succeeded by his son Ibrahim II, who upon his death was replaced by Ismail in 1443.
After his conquest of Constantinople in 1453, the Ottoman sultan Mehmed II turned to Anatolia to unite the Anatolian beyliks and principalities under his rule. In 1461, joining forces with Ismail's brother Ahmed (the Red), he captured Sinop and ended the official reign of the Jandarid dynasty, although he appointed Ahmed as the governor of Kastamonu and Sinop, only to revoke Ahmed's appointment the same year. According to new research, this seems to have happened in 1464.
Following the incorporation of the principality in the Ottoman Empire, the ruling dynasty was offered various important functions within the Ottoman administration, which they maintained until its collapse in 1922. Descendants of the Jandarid dynasty live today as citizens of the Turkish Republic mostly in Istanbul and in Europe, using various family names. Ayşe Sultan, who was the last identified descendant of the Jandarid dynasty, having benefited from the status offered by the Ottoman Empire to the dynasty, died in 1981 in Ankara.