Regula Est
The Cyclopedic Law Dictionary · Walter A. Shumaker and George Foster Longsdorf; ed. James C. Cahill · 1922
The Cyclopedic Law Dictionary
JURIS QUIDEM IGNOrance of law does not excuse, but that ignorance of a fact may excuse a party from the legal consequences of his conduct.
Dig. 22. 6. 9; Broom, Leg. Max. (3d London Ed.) 232. See Irving, Civ. Law (4th Ed.) 74.