Council of Constance

==Decrees and doctrinal status==
[[File:Richental Konzilssitzung Muenster.jpg|thumb|right|Bishops debating with the pope at the Council of Constance]]
Many members of the new assembly (comparatively few bishops, but many doctors of theology and of canon and civil law, procurators of bishops, deputies of universities, cathedral chapters, provosts, etc., agents and representatives of princes, etc.) strongly favored the voluntary abdication of all three popes, as did King Sigismund.{{sfn|Shahan|1908}}

Although the Italian bishops who had accompanied John XXIII in large numbers supported his legitimacy, he grew increasingly more suspicious of the council. Partly in response to a fierce anonymous attack on his character from an Italian source, on 2 March 1415 he promised to resign. However, on 20 March he secretly fled the city and took refuge at Schaffhausen in territory of his friend Frederick, Duke of Austria-Tyrol.{{sfn|Shahan|1908}}

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:

{{blockquote|sign=|source=|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.{{efn|For good, brief discussions of the politics of conciliarism at and after Constance, see {{harvnb|Black|1998|pp= 67–76}} and {{harvnb|Watts|2009|pp=291–301}} }}<ref name="Piar" /> 

The acts of the council were not made public until 1442, at the behest of the [[Council of Basel]]; they were printed in 1500. The creation of a book on how to die was ordered by the council, and thus written in 1415 under the title ''[[Ars moriendi]]''.

''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. On this reading, the first sessions of the Council of Constance represented an invalid and illicit assembly of bishops, gathered under the authority of an antipope. This historiography is of much later provenance than the council itself, however: the Pisan line represented by John XXIII had been considered legitimate not just by most of the Latin church at the time of the council, but also subsequently by Pope Martin V, who referred to John as "our predecessor" in contrast to the other two claimants, who were merely "popes so-called in their obediences". 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]].{{sfn|Oakley|2003|pp=86–87}}