The Madrid Codices I–II (I – Ms. 8937 i II – Ms. 8936), are two manuscripts by Leonardo da Vinci which were discovered in the Biblioteca Nacional de España in Madrid in 1965 by Dr. Jules Piccus, Language Professor at the University of Massachusetts. The Madrid Codices I was finished during 1490 and 1499, and II from 1503 to 1505.The two codices were brought to Spain by Pompeo Leoni, a sculptor in the court of Philip II. After various changes of ownership, they were transferred to the monastic library of El Escorial and finally to the Biblioteca Real, where they remained unknown for 252 years.