Gratian's Decretum
Cologne Dombibliothek 127, fol. 10r, ca. 1160 A.D.
Gratian Decretum, D.4 dictum post c.3
Leges instituntur cum promulgantur, firmantur cum moribus utentium approbantur (Laws are established when they are promulgated and they are confirmed when they have been approved by the long term and reasoned acceptance of those who observe them).