The council also condemned Jan Hus as a heretic and facilitated his execution; and it ruled on issues of national sovereignty and the rights of pagans and just war in response to a conflict between the Grand Duchy of Lithuania, the Kingdom of Poland and the Order of the Teutonic Knights.

Though Haec sancta, at least, continued to be accepted as binding by much of the church up to the 19th century, present-day Catholic theologians generally regard these decrees as either invalid or as practical responses to a particular situation without wider implications.

After thirty years of schism, the rival courts convened the Council of Pisa seeking to resolve the situation by deposing the two claimant popes and electing a new one.

[3] Sigismund arrived on Christmas Eve 1414 and exercised a profound and continuous influence on the course of the council in his capacity of imperial protector of the church.

The Spanish deputies (from Portugal, Castile, Navarre and Aragon), initially absent, joined the council at the twenty-first session, constituting upon arrival the fifth nation.

[4] Although the Italian bishops who had accompanied John XXIII in large numbers supported his legitimacy, he grew increasingly more suspicious of the council.

[4] The famous decree Haec sancta synodus, which gave primacy to the authority of the council and thus became a source for ecclesial conciliarism, was promulgated in the fifth session, 6 April 1415: Legitimately assembled in the holy Spirit, constituting a general council and representing the Catholic church militant, it has power immediately from Christ; and everyone of whatever state or dignity, even papal, is bound to obey it in those matters which pertain to the faith, the eradication of the said schism, and the general reform of the said church of God in head and members.Haec sancta synodus marks the high-water mark of the Conciliar movement of reform.

Haec sancta is today generally considered invalid by the Catholic Church, on the basis that Gregory XII was the legitimate pope at the time and the decree was passed by the council in a session before his confirmation.

The specific argument distinguishing two parts in the council was seemingly first made by the 17th-century Sorbonne theologian André Duval, and remained a fringe view for some time before its vindication within the Catholic Church under the influence of 19th-century ultramontanism.

[7] Gregory XII then sent representatives to Constance, whom he granted full powers to summon, open, and preside over an Ecumenical Council; he also empowered them to present his resignation of the papacy.

On 4 July 1415 the Bull of Gregory XII which appointed Dominici and Malatesta as his proxies at the council was formally read before the assembled Bishops.

Prince Malatesta immediately informed the council that he was empowered by a commission from Pope Gregory XII to resign the Papal Throne on the Pontiff's behalf.

The reforms were largely directed against John Wycliffe, mentioned in the opening session and condemned in the eighth on 4 May 1415, and Jan Hus, along with their followers.

Hus, summoned to Constance under a letter of safe conduct, was found guilty of heresy by the council and turned over to the secular court.

The Polish-Lithuanian position was defended by Paulus Vladimiri, rector of the Jagiellonian University, who challenged legality of the Teutonic crusade against Lithuania.

In his Liber de doctrina, Falkenberg argued thatthe Emperor has the right to slay even peaceful infidels simply because they are pagans. ...

[9] Other opponents included Grand Master's proctor Peter Wormditt, Dominic of San Gimignano, John Urbach, Ardecino de Porta of Novara, and Bishop of Ciudad Rodrigo Andrew Escobar.

Pope Martin V appointed the Lithuanians Jogaila and Vytautas, who were respectively King of Poland and Grand Duke of Lithuania, as vicars general in Pskov and Veliky Novgorod in recognition of their Catholicism.

[13] Either way, while Rome itself came to reject the provisions made by the council, significant parts of the Church, notably in France, continued to uphold the validity of its decisions long after the event: Haec sancta was reaffirmed in the Gallican Articles of 1682, and even during the First Vatican Council of 1869–70 the French-American bishop of St. Augustine, Florida, Augustin Vérot, attempted to read Haec sancta into the record of deliberations.