The candar corps was the name given to palace guards in Turkish and Islamic states in the middle ages. Also in Persian and in some Arab states, certain soldier classes were also called candar. They were especially assigned to guard palaces and the heads of state.
In the Great Seljuk Empire, the candar corps consisted of specially trained Turkish and foreign slaves. The head of the candar corps was called Emir-i Candar and he was included in the governing body. After the break up of the empire, some members of this corps went to the Turkomanbeyliks in Anatolia, Shiraz, Khorasan, and through the Mamluks to Yemen and Maghreb states to take up being palace guards.
In Anatolian Seljuks (Sultanate of Rüm), candars guarded the palace and the head of state and his headquarters, together with the Hassa soldiers. They were cavalrymen, and they would use swords, bows and carry shields. One of these candars who actually was in the Seljuk court, Demir Yaman Candar, founded his own Anatolian beylik Candaroglu, near Kastamonu, Turkey.
In the Mamluk palace, the candar corps was as large as a regiment, and was divided into smaller units called nevbe. They had wider authorities and responsibilities, such as accompanying those who would enter the court, accompanying the monarch himself at campaigns to protect him, performing arrests and executions, as well as guarding the prison allocated to political insurgents.
The Ottoman Turks did not have candars at their courts; instead they had set up a different institution to take up their position.
The Empire had suffered hard from the Interregnum; the Mongols where still at large in the east, even though Timur Lenk had died in 1405; many of the Christian kingdoms of the Balkans had broken free of Ottoman control; and the land, especially Anatolia, had suffered hard from the war.
During his reign, Mehmed moved the capitol from Bursa to Adrianople (Edirne), reinforced control over Bulgaria and Serbia, drove the Mongols from Anatolia and assaulted Albania, Cilicia, the Turkish emirate of Candar and Byzantine controlled areas in southern Greece.
The war between Serbia and Hungaria and the Ottoman Empire had come to a standstill in 1441 when the Holy Roman Empire, Poland, Albania, and the emirates Candar and Karaman (in violation of the peace treaty) intervened against the Ottomans.