Lex posterior derogat priori - "Later law removes the earlier." More recent law overrules older ones on the same matter.⏎
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.⏎
Leges humanae nascuntur, vivunt, moriuntur - "The laws of man are born, live, and die." Illustrates that laws are made, are in force for a period, and then become obsolete.⏎
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.⏎