England and visited the universities of Paris and Oxford before arriving in Flanders in 1426, where he spent the next two years at the Burgundian court. After the death of the second wife of Philip the Good of Burgundy in 1425, Peter recommended his sister Isabella to him as a wife. Philip sent a delegation to Portugal in 1428–29 that included Jan van Eyck, who painted two portraits of the Infanta. Philip and Isabella eventually married on 7 January 1430, and one of their sons became Duke Charles the Bold of Burgundy. In 1427, Peter wrote a famous letter to his older brother, later King Edward, on "the proper administration of the kingdoms", from Bruges. Later that year, King Henry VI of England (his first cousin once removed) made him a Knight of the Garter (as were already his father and older brother Edward). In 1428, Peter visited his marquisate of Treviso and the nearby Republic of Venice, where he was presented with a copy of the book of Marco Polo by the doge. He later gave that book, as well as maps of the Venetian trade routes in the Orient, to his younger brother Prince Henry the Navigator. One of the maps was created by the famous Venetian cartographer Albertinus de Virga in 1411 and possibly shows North America before it was officially discovered. This map was found in the Alcobaça Monastery which was the main library of the Portuguese Royal family. From Venice he traveled to Rome, where he was received by Pope Martin V, and from there he continued to Barcelona, where he negotiated the marriage of his brother Edward with Eleanor of Aragon as well as his own future marriage with Isabella of Urgell, before finally returning to Portugal. In 1433, he completed his famous six-volume work, the Tratado da Virtuosa Benfeitoria. Regent When Peter's brother King Edward I of Portugal died in 1438, Peter's nephew Afonso V ascended the throne as an infant. At first, the choice for regent was the Queen mother Eleanor of Aragon. This choice was not popular among many Portuguese, because Eleanor was Aragonese. Among the Portuguese aristocracy, however, especially among nobles around Peter's half-brother Afonso, Count of Barcelos, Eleanor of Aragon was preferred. There were also doubts about Peter's political ability. At a meeting of the Portuguese Cortes summoned by Peter's brother John, Lord of Reguengos de Monsaraz, Peter was