The subject of mistake belongs to the matters which still appear to be very confused nowadays. The treatment of mistake is regarded as one of the weakest aspects of classical contract law. This article aims at tracing the developments of the principles of mistake in contract from Roman law, through the reception of Roman law in the medieval and the influence of natural law on the enactments of civil codes in the 18th century, until the Historical school and the school of Pandecten in the beginning of the 20th century. In the nineteenth century, especially the ideas of Pothier were received into the common law by the treaties writers and judges.