TRENDEFRAtlas of the Sultans · Glossary
Term · Provinces and land
Also known as: frontier lord, uç
A bey who organised raids in a border zone (uç) and governed the region.
The word uç means “frontier”. The Turkmen lords who appeared along the Byzantine border as the Anatolian Seljuk state broke up are called uç beyi, and the principalities they founded uç beyliği. The Ottoman principality itself was born as such a frontier principality; in Rumelia, frontier families such as the Evrenosoğulları and the Mihaloğulları played a leading role in the conquests.
Source: TDV Encyclopedia of Islam, article “UÇ BEYİ” (in Turkish); text condensed for the atlas.