He created the church of S. Vincenzo, which had belonged to the monastery of Ss. Lucilla and Flora, the new cathedral. In a bull of 29 June 1325, the Pope designated Rinaldo di Guido, parish priest of S. Andrea, the new Provost of the cathedral. In another bull, dated 30 June 1325, Pope John established the cathedral Chapter, composed of two dignities (Provost and Archdeacon) and eight Canons. The current Cathedral of Cortona became the diocesan seat only in 1507. The diocesan seminary was founded by Bishop Francesco Perignani (1572–1577) in 1573. A diocesan synod was an irregularly held, but important, meeting of the bishop of a diocese and his clergy. Its purpose was (1) to proclaim generally the various decrees already issued by the bishop; (2) to discuss and ratify measures on which the bishop chose to consult with his clergy; (3) to publish statutes and decrees of the diocesan synod, of the provincial synod, and of the Holy See. Bishop Giovanni Alberti (1585–1596) presided over a diocesan synod in 1588. Bishop Cosmo Minerbetto conducted a diocesan synod in Cortona in 1624. A diocesan synod was held in Cortona in August 1634 by Bishop Lorenzo della Robbia. On 18 February 1984, the Vatican and the Italian State signed a new and revised concordat. Based on the revisions, a set of "Normae" was issued on 15 November 1984, which was accompanied in the next year, on 3 June 1985, by enabling legislation. According to the agreement, the practice of having one bishop govern two separate dioceses at the same time, "aeque personaliter", was abolished. Instead, the Vatican continued consultations which had begun under Pope John XXIII for the merging of small dioceses, especially those with personnel and financial problems, into one combined diocese. In Tuscany, this particularly affected three dioceses: Arezzo, Cortona, and Borgo San Sepolcro (Biturgensis). On 30 September 1986, Pope John Paul II ordered that the dioceses of Arezzo, Cortona, and San Sepolcro be merged into one diocese with one bishop, with the Latin title "Dioecesis Arretina-Cortonensis-Biturgensis".