As an English name, Aaron has been in use since the Protestant Reformation. This name was borne by the American politician Aaron Burr (1756-1836), notable for killing Alexander Hamilton in a duel.
Roland was an 8th-century military commander, serving under Charlemagne, who was killed by the Basques at the Battle of Roncevaux. His name was recorded in Latin as Hruodlandus. His tale was greatly embellished in the 11th-century French epic La Chanson de Roland, in which he is a nephew of Charlemagne killed after being ambushed by the Saracens. The Normans introduced the name to England.