His knowledge of canon law, noble lineage, and austere way of life won him the approval of Pope Gregory XI, who appointed de Luna to the position of Cardinal Deacon of Santa Maria in Cosmedin on 20 December 1375.

The conclave duly elected Bartolomeo Prignano, Archbishop of Bari, as Urban VI on 9 April, but the new pope proved to be intractably hostile to the cardinals.

[1] Clement VII sent de Luna as legate to Spain for the Kingdoms of Castile, Aragon, Navarre, and Portugal, in order to win them over to the obedience of the Avignon pope.

On the death of Urban VI in 1389, the Roman College of Cardinals had chosen Boniface IX; the election of Benedict therefore perpetuated the Western Schism.

At the start of his term of office, de Luna was recognised as pope by France, Scotland, Sicily, Castile, Aragon and Navarre.

In 1396, Benedict sent Sanchez Muñoz, one of the most loyal members of the Avignon curia, as an envoy to the Bishop of Valencia to bolster support for the Avignon-based papacy in the Crown of Aragon.

Since both Benedict and Gregory refused to abdicate, the only achievement in Pisa was that a third candidate to the Holy See was put forward: Peter Philarghi, who assumed the name Alexander V.[4] A group of Augustinian clergy, driven from the University of Paris by the Schism and from the universities of Oxford and Cambridge by the Anglo-Scottish Wars, formed a society of higher learning in St Andrews, Fife, Scotland in 1410.

The Bishop of St Andrews, Henry Wardlaw, then successfully petitioned Benedict to grant the school university status by issuing a series of papal bulls, which followed on 28 August 1413.

Gregory XII agreed to resign, and Baldassare Cossa, who had succeeded Philarghi as the Pisan papal contender in 1410 and had assumed the name John XXIII, tried to flee and was deposed during his absence, being subsequently tried upon his return.

Finally, Emperor Sigismund organised a European summit in Perpignan, to convince Benedict to resign his office and end the Western Schism.

[10] Because of this stubbornness, the Council of Constance declared Benedict a schismatic and excommunicated him from the Catholic Church on 27 July 1417, and elected Martin V as the new consensual pope on 11 November 1417.

[4] The day before his death, Benedict appointed four cardinals of proven loyalty to ensure the succession of another pope who would remain faithful to the now beleaguered Avignon line.

When, in 1429, an agreement between Rome and Aragon was reached, Clement VIII abdicated in favour of recognising Pope Martin V, terminating the Avignon line of anti-popes.

[13] On 21 December 2018, the association "Friends of Pope Luna" presented to the Congregation for the Doctrine of the Faith a petition to have Benedict recognised as a legitimate pontiff.

[14][15] The Anti-pope (Peter de Luna, 1342–1423): A study in obstinacy by Alec Glasfurd, Roy Publishers, New York (1965) B0007IVH1Q is a somewhat fictionalised or imaginative account of his life.