1650s as an architectural order, from Corinth, the ancient Greek city-state. In classical times Corinth was notorious for its luxury and licentiousness among the Greek states (and for not scorning trade and profit); hence Corinthian, noun and adjective, in various slang or colloquial sense in English, especially "a swell, a man about town" (early to mid-19c. but especially in the 1820s).
