Lex retro non agit - "The law does not operate retroactively." A law cannot make something illegal that was legal at the time it was performed. See ex post facto law.⏎
Nemo dat quod non habet - [6] The basic rule that a person who does not own property (e.g. a thief) cannot confer it on another except with the true owner's authority (i.e. as his agent). Exceptions to this rule include sales under statutory powers, and cases where the doctrine of estoppel prevents a legal owner from denying a seller's right to sell.⏎
Jura novit curia - "The court knows the law." Concept that parties to a case do not need to define how the law applies to their case. The court is solely responsible for determining what laws apply.⏎
Maleficia propositis distinguuntur - "Evil acts are distinguished from (evil) purposes" or "crimes are distinguished by evil intent." Evil acts are distinguished from evil purposes[4] crimes are distinguished by the intention[5]⏎