Early 19th century; earliest use found in Walter Scott (1771–1832), poet and novelist. From French revenons à nos moutons, lit. ‘let us return to our sheep’, originally an allusion to the line Sus! revenons à ces moutons ‘Come now! let us return to these sheep’, spoken by a judge seeking to bring a digressing litigant back to the question of some stolen sheep in a court scene in the Farce de Maistre Pierre Pathelin.