The Black Death struck the whole of Scandinavia except Iceland; in Norway, in particular, its effects were aggravated by subsequent epidemics, smallpox in 1359-60, plague in 1371. In the political history of the Scandinavian countries, Denmark, Finland, Iceland and the states of the Scandinavian peninsula, Norway and Sweden, the long fifteenth century from c.1390 to the Reformation forms a well-defined period. In Sweden, the resumption of alienated crown lands had aroused the opposition of the Church. The Great Schism having undermined the authority of the Papacy, the general council emerged as the leading ruling body of the Church. Sweden had deposed Erik and was ruled by Karl Knutsson as regent. In the winter of 1439-40 Erik concluded an alliance with the overlord of the Low Countries, Duke Philip of Burgundy. The battle of Brunkeberg was a turning-point in Scandinavian history. The riksråd, convoked to meet on 30 October, declared on the following day that Christian was lawful heir to Sweden.

Supporters of the conciliar way wanted the council to undertake a reform of the Church, especially of papal taxation and papal appointments to senior benefices. On 26 June Peter Philarge, cardinal-archbishop of Milan, was elected pope and took the name Alexander V. The ensuing military and political events had a decisive impact on church history. The project of reunion through a council had been attracting strong support among the universities, especially Paris, and the numerous clerics, including senior prelates, who had been educated there. The defeat of the Council of Basle proved decisive for the western Church, for western Christendom and for European civilisation. Public opinion, amongst intellectuals and in court circles, seems to have favoured the more moderate view that a council was the emergency superior of the pope in cases of heresy, schism and the urgent need for reform. A look at popes and councils shows that the politics and ideology had an effect in shaping European culture.