Reasons: The reasons for classification of invalidity cases can be grouped under three main headings as initial impossibility, illegality and immorality.
A- Initial Impossibility: It is the impossibility of the subject of the legal transaction while establishing the legal transaction. In this case, the legal action will be invalid. For example, the fact that a completely burned house is the subject of a purchase and sale contract renders this legal transaction invalid. That is, something that does not exist cannot be sold. For the initial impossibility to be asserted and passed on, the situation must be objective. There was no question of buying and selling items used for religious purposes in Rome. Therefore, the purchase and sale contract, which was the subject of religious tools, was invalid.
B- Unlawful: Legal transactions are invalid if they are against the law. Although the sources of law changed according to the political periods of Rome, especially the 12-plate law, the decisions of the people’s assembly, the decisions of the praetor, the emperor’s orders, and the Corpus Iurus Civilis during the Justinian period were the sources of law. Therefore, when a legal action was taken contrary to these legal sources, the legal action was invalid. According to the Roman property law, transactions were made according to the distinction between “res mancipi” and “res nec mancipi”. For these, too, “mancipatio” and “in iure cessio” legal rituals were performed. These procedures are prescribed by law. Therefore, the transfer of ownership of the goods must be made according to these transactions. If the transfer of ownership of the goods was not made according to these procedures, the legal proceedings would be invalid. Again in Rome, there is an oral legal act called “stipulatio”, which is frequently seen in the law of obligations. This transaction is a legal transaction established by mutually speaking certain words. Here, the words that the parties have to say to each other are the form. Therefore, legal proceedings that did not comply with the form requirement of the stipilatio were deemed invalid.
C- Immorality: The subject and purpose of legal proceedings in Rome must not be against morality. Therefore, legal actions taken against the general moral rules are invalid. For example, if a company was established for the purpose of doing illegitimate business, that company’s contract would be void.
