The meaning of this name is not known for certain. It was used in Brittany at least as early as the 6th century, and it possibly means either "little rock" or "handsome" in Breton. Alternatively, it may derive from the tribal name of the Alans, an Iranian people who migrated into Europe in the 4th and 5th centuries.
This was the name of several dukes of Brittany, and Breton settlers introduced it to England after the Norman conquest. Famous modern bearers include Alan Shepard (1923-1998), the first American in space and the fifth man to walk on the moon, and Alan Turing (1912-1954), a British mathematician and computer scientist.