c. 1200, "ruler of a principality" (mid-12c. as a surname), from Old French prince "prince, noble lord" (12c.), from Latin princeps (genitive principis) "first man, chief leader; ruler, sovereign," noun use of adjective meaning "that takes first," from primus "first" (see prime (adj.)) + root of capere "to take," from PIE root *kap- "to grasp."
German cognate fürst, from Old High German furist "first," is apparently an imitation of the Latin formation. Colloquial meaning "admirable or generous person" is from 1911, American English. Prince Regent was the title of George, Prince of Wales (later George VI) during the mental incapacity of George III (1811-1820).