notably used reason and logic to dismiss the superstitious foundations of the ordeal; for example, the use of trial by hot iron was dismissed because people believed "the natural heat of white-hot iron grows hot and, what is even more foolish, grows cold for no good reason at all", and trial by water was forbidden because of the belief "that the defendant of the crime, who has been established only by his guilty conscience, will not be received by the element of freezing water, when, in fact, it is the retention of sufficient air that prevents him from submerging." Frederick also banned trial by battle, ordering that more weight be given to the testimony of witnesses, although exceptions to this were granted to knights, and for cases in which no witnesses could be provided. The Constitutions also contain incidental information relating to the practice of medicine. Frederick proclaimed that, in order to become a medical practitioner, it was necessary to have some practical experience, which many European university-educated doctors did not have in 1231. According to Ernst Kantorowicz, the Liber "is the birth certificate of the modern administrative state." The Constitutions of Melfi remained applicable law in the Kingdom of Naples until 1809 and in Sicily until 1819. Editions and translations Constitutionum Regni Siciliarum (ed. 1773) Literature David Abulafia, Frederick II. A Medieval Emperor (1988), chapter six. Messana, Federico. Liber Augustalis o Costituzioni melfitane (1231). Notes Medieval legal codes 1231 in Europe 1230s in law Frederick II, Holy Roman Emperor 13th century in the Kingdom of Sicily