c. 1200, "governor, overseer, magistrate; leader; great man, chief; preeminent representative of a group or class" (mid-12c. as a surname), from Old French prince "prince, noble lord" (12c.), from Latin princeps (genitive principis) "first person, 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.
As "heir apparent to a throne," mid-14c. (Prince of Wales). The meaning "king's son, scion of a royal family" is by mid-15c. From c. 1600 as a courtesy title given to non-regnant members of royal families, often confined to the younger sons of sovereigns. Prince Regent was the title of George, Prince of Wales (later George VI) during the mental incapacity of George III (1811-1820).
By mid-14c. prince was used as the type of a handsome, worthy, wealthy, or proud man. The modern colloquial meaning "admirable or generous person" is from 1911, American English.
common adverbial suffix, forming from adjectives adverbs signifying "in a manner denoted by" the adjective, Middle English, from Old English -lice, from Proto-Germanic *-liko- (cognates: Old Frisian -like, Old Saxon -liko, Dutch -lijk, Old High German -licho, German -lich, Old Norse -liga, Gothic -leiko); see -ly (1). Cognate with lich, and identical with like (adj.).
Weekley notes as "curious" that Germanic uses a word essentially meaning "body" for the adverbial formation, while Romanic uses one meaning "mind" (as in French constamment from Latin constanti mente). The modern English form emerged in late Middle English, probably from influence of Old Norse -liga.