La Laesio Ultradimidium no nació en Roma para proteger a la parte más débil de una relación jurídica considerada en abstracto, sino únicamente para defender a los enajenantes que se vieron perjudicados, cuando cobraron menos de la mitad de lo que el objeto vendido valía. Apareció tarde en el Derecho Romano, pese a que su creación se atribuya a Diocleciano, ya que en realidad es una creación post clásica, concretamente justinianea. Y su verdadero desarrollo se produce con la Glosa y el Derecho Canónico.
The Laesio Ultradimidium was not created in Rome to protect anyone who was the weak party in a legal relationship. It was born in order to give protection only to sellers, that have earned the half or less of the real valuation that the thing sold had. The institute was created during the period of late Roman Law, because if it is true that appears as an invention of Diocletian emperor, the real fact instead is that was introduced by Justinian emperor in his Corpus Iuris. An the development of that legal institution takes place through the Glossa Magna and Canonic Law.