Pope Eugene IV in the context of "Liber Pontificalis"

The Council of Florence is the seventeenth ecumenical council recognized by the Catholic Church, held between 1431 and 1445. It was convened in territories under the Holy Roman Empire. Italy became a venue of a Catholic ecumenical council after a gap of about 2 centuries (the last ecumenical council to be held in Italy was the 4th Council of the Lateran in Rome's Lateran Palace). It was convoked in Basel as the Council of Basel by Pope Martin V shortly before his death in February 1431 and took place in the context of the Hussite Wars in Bohemia and the rise of the Ottoman Empire. At stake was the greater conflict between the conciliar movement and the principle of papal supremacy.

The Council entered a second phase after Emperor Sigismund's death in 1437. Pope Eugene IV translated the Council to Ferrara on 8 January 1438, where it became the Council of Ferrara and succeeded in drawing some of the Byzantine ambassadors who were in attendance at Basel to Italy. Some Council members rejected the papal decree and remained at Basel: this rump Council suspended Eugene, declared him a heretic, and then in November 1439 elected an antipope, Felix V.

Pope Nicholas V (Latin: Nicolaus V; Italian: Niccolò V; 15 November 1397 – 24 March 1455), born Tommaso Parentucelli, was head of the Catholic Church and ruler of the Papal States from 6 March 1447 until his death in March 1455. Pope Eugene IV made him a cardinal in 1446 after successful trips to Italy and Germany, and when Eugene died the next year, Parentucelli was elected in his place. He took his name Nicholas in memory of his obligations to Niccolò Albergati. He remains the most recent pope to take the pontifical name "Nicholas".

The pontificate of Nicholas saw the fall of Constantinople to the Ottoman Turks and the end of the Hundred Years' War. He responded by calling a crusade against the Ottomans, which never materialized. By the Concordat of Vienna he secured the recognition of papal rights over bishoprics and benefices. He also brought about the submission of the last of the antipopes, Felix V, and the dissolution of the Synod of Basel. A key figure in the Roman Renaissance, Nicholas sought to make Rome the home of literature and art. He strengthened fortifications, restored aqueducts, and rebuilt many churches. He ordered design plans for what would eventually be the Basilica of St. Peter.

The Crusade of Varna was an unsuccessful military campaign mounted by several European leaders to check the expansion of the Ottoman Empire into Central Europe, specifically the Balkans between 1443 and 1444. It was called by Pope Eugene IV on 1 January 1443 and led by King Władysław III of Poland, John Hunyadi, Voivode of Transylvania, and Duke Philip the Good of Burgundy.

The Crusade of Varna culminated in a decisive Ottoman victory over the crusader alliance at the Battle of Varna on 10 November 1444, during which Władysław disappeared and the expedition's papal legate Julian Cesarini was killed.

Guillaume Du Fay (/djuːˈfaɪ/ dyoo-FEYE, French: [ɡijom dy fa(j)i]; also Dufay, Du Fayt; 5 August 1397 – 27 November 1474) was a composer and music theorist of early Renaissance music, who is variously described as French or Franco-Flemish. Considered the leading European composer of his time, his music was widely performed and reproduced. Du Fay was well-associated with composers of the Burgundian School, particularly his colleague Gilles Binchois, but was never a regular member of the Burgundian chapel himself.

While he is among the best-documented composers of his time, Du Fay's birth and family is shrouded with uncertainty, though he was probably the illegitimate child of a priest. He was educated at Cambrai Cathedral, where his teachers included Nicolas Grenon and Richard Loqueville, among others. For the next decade, Du Fay worked throughout Europe: as a subdeacon in Cambrai, under Carlo I Malatesta in Rimini, for the House of Malatesta in Pesaro, and under Louis Aleman in Bologna, where he was ordained priest. As his fame began to spread, he settled in Rome in 1428 as musician of the prestigious papal choir, first under Pope Martin V and then Pope Eugene IV, where he wrote the motets Balsamus et munda cera, Ecclesie militantis and Supremum est mortalibus. Amid Rome's financial and political disorder in the 1430s, Du Fay took a leave of absence from the choir to serve Amadeus VIII, Duke of Savoy.

Niccolò Albergati (1373 – 9 May 1443) was an Italian Carthusian and a prelate of the Roman Catholic Church. He was appointed cardinal and served as a papal diplomat to France and England (1422–23) in addition to serving as the bishop of Bologna from 1417 until his death.

He accepted the position as bishop in obedience despite his extreme reluctance to accept the position but carried out his duties with care and attention to educational concerns. But two conflicts in his see caused him to depart and later return and he became known for being close to Pope Martin V and his successor Pope Eugene IV. Both men held Albergati in high esteem and nominated him to crucial positions within the Roman Curia and the diplomatic service to oversee important missions. He had prominent roles in the Council of Basel-Ferrara-Florence and also attended the Council of Florence.

The Liber Pontificalis (Latin for 'pontifical book' or Book of the Popes) is a book of biographies of popes from Saint Peter until the 15th century. The original publication of the Liber Pontificalis stopped with Pope Adrian II (867–872) or Pope Stephen V (885–891), but it was later supplemented in a different style until Pope Eugene IV (1431–1447) and then Pope Pius II (1458–1464). Although quoted virtually uncritically from the 8th to 18th centuries, the Liber Pontificalis has undergone intense modern scholarly scrutiny. The work of the French priest Louis Duchesne (who compiled the major scholarly edition), and of others has highlighted some of the underlying redactional motivations of different sections, though such interests are so disparate and varied as to render improbable one populariser's claim that it is an "unofficial instrument of pontifical propaganda."

The title Liber Pontificalis goes back to the 12th century, although it only became current in the 15th century, and the canonical title of the work since the edition of Duchesne in the 19th century. In the earliest extant manuscripts it is referred to as Liber episcopalis in quo continentur acta beatorum pontificum Urbis Romae ('episcopal book in which are contained the acts of the blessed pontiffs of the city of Rome') and later the Gesta or Chronica pontificum.