1. A term in a contract of sale allowing the seller to rescind the sale if the price was not paid by the agreed time.
2. A clause by which, in a pledge agreement, a debtor and creditor could agree that if the debtor fails to timely pay the debt, the creditor obtains absolute title of the pledged property.
“By the lex commissoria at Rome, the debtor and creditor might agree that if the debtor did not pay at the day, the pledge should become the absolute property of the creditor. But a law of Constantine abolished this power, as unjust and oppressive, and having a growing asperity in practice.” 2 James Kent, Commentaries on American Law *583 (George Comstock ed., 11th ed. 1866).
3. An agreement in which such a failure-to-timely-pay clause appears. — Also written commissoria lex.
4. LEX COMMERCII.“But the position of the seller was a good deal more awkward, especially if he had sold a unique object, such as a piece of land, for, apart from express agreement, he would have to retain the land or other object in case the buyer later came along with the price and demanded delivery. The difficulty could be avoided by the insertion of a term known as lex commissoria, which gave the seller an option of declaring the contract at an end if the buyer did not pay within the agreed time. This term probably became common form in Roman law, but was never implied. It always had to be expressly inserted in the contract …. Not until the time of Lord Mansfield was a similar development complete in English law, though in the end we carried it much further than the Romans.” W.W. Buckland & Arnold D. McNair, Roman Law & Common Law: A Comparison in Outline 231 (F.H. Lawson ed., 2d ed. 1952).
