"a lord-master, a protector," c.1300, from O.Fr. patrun (12c.), from M.L. patronus "patron saint, bestower of a benefice, lord, master, model, pattern," from L. patronus "defender, protector, advocate," from pater (gen. patris) "father." Meaning "one who advances the cause" (of an artist, institution, etc.), usually by the person's wealth and power, is attested from 1377; "commonly a wretch who supports with insolence, and is paid with flattery" [Johnson]. Commercial sense of "regular customer" first recorded 1605.