+The **Duke of Lancaster** is a historic [English](/wiki/english) ducal title, intrinsically linked to the [Duchy of Lancaster](/wiki/duchy_of_lancaster). Since 1399, the title has merged with the [Crown](/wiki/crown), making the reigning British monarch the perpetual Duke.
+## See also
+- [House of Lancaster](/wiki/house_of_lancaster)
+- [British Monarchy](/wiki/british_monarchy)
+- [Peerage](/wiki/peerage)