Theses de emptione et venditione

XX.

And the buyer is granted the action of buying, and the seller the action of selling, both of which are of good faith, personal, and direct.

XXI.

Although, when buying and selling is rightly perfected, one is not allowed to repent: yet by agreements, such as the lex commissoria forfeiture clause, or if by error or against good faith the buyer or seller has been harmed beyond half of the just price, by the persuasion of equity and by the law of the constitution of the Emperor Diocletian Code of Justinian, Book 4, Title 44, Law 2, this contract is rescinded.

A woodcut emblem depicts the mythological figure Arion standing on the back of a dolphin in the sea, holding a lyre. He is surrounded by an oval frame containing the Latin inscription: "Arion. There is no way impassable for virtue. Fates find a way."