Prior tempore potior iure - "Earlier in time, stronger in law". A legal principle that older laws take precedence over newer ones. Another name for this principle is lex posterior.⏎
Qui facit per alium facit per se - "Who acts through another, acts himself." One who delegates a task to another, takes full responsibility for the performance of that act as if he himself had done it. Basis for the law of agency.⏎
Quod est necessarium est licitum - What is necessary is lawful.⏎
Pacta sunt servanda - Agreements must be kept. Contracts are the law or contracts establish obligations (between those who sign them).⏎
Par in parem non habet imperium - Equals have no sovereignty over each other.⏎