and he removed the requirement that Doctors of Medicine be in holy orders. He then presided over the Assembly of the French clergy which met at Bourges in July and August 1452 to discuss the implementation of the Pragmatic Sanction. He finally returned to Rome on 3 January 1453, where he passed almost all the rest of his life. D'Estouteville, appointed Legate to the King of France, set out from Rome for France on 16 May 1454, with permission to be outside the Curia for six months; he returned to Rome on 12 September 1455 after sixteen months absence. His official mission was to attempt to persuade Charles VII to join in yet another crusade, the one that Nicholas V had tried to launch on 30 September 1453, following the Fall of Constantinople. Rome On his return, he built as his residence the Palazzo Apollinare to the west of the Church of S. Agostino and adjacent to the Church of S. Apollinare. Conclaves D'Estouteville participated in the papal conclave of 4–10 March 1447 that elected Pope Nicholas V. He was absent from Rome, however, during the sede vacante of 24 March–8 April 1455, prior to the election of Pope Calixtus III. D'Estouteville took part in the Conclave of 6–19 August 1458 and was a candidate for the papacy in the Conclave; he was able to command six votes out of the nineteen participants, but he was defeated by Cardinal Aeneas Sylvius Piccolomini of Siena, who chose the name Pope Pius II. On 20 February 1456 he was one of the cardinals who subscribed the bull of Pope Calixtus III which created Rodrigo Borgia a cardinal. In 1458 Cardinal d'Estouteville was asked by the Teutonic Knights to be their Protector at the Roman Curia, an honor and office which he accepted. D'Estouteville also was cardinal protector of the Augustinian Hermits. In January 1459 he accompanied Pope Pius II in his journey to Mantua to meet with the princes of Europe to arrange for a crusade against the Ottoman Turks. He became Cardinal Bishop of Porto-Santa Rufina on 19 March 1459. He was named the Cardinal-Bishop of Ostia on 26 October 1461, and became the Dean of the College of Cardinals after the death of Cardinal Bessarion on 18 November 1472. He took part in the Conclave of 27/28–30 August 1464, in which Pope Paul II (Pietro Barbo of Venice) was elected