The confused and tumultuous circumstances surrounding the election to the papacy of Urban VI, its corollaries, the subsequent defection of thirteen of the cardinals, their election of a rival pontiff, and the ensuing years of dismal division within the Church—these form the general background to this tract, which is a product, therefore, of the immense outburst of polemical writing occasioned by the onset, in 1378, of the Great Schism. The more immediate circumstances surrounding it are the failure by 1403 of the French withdrawal of obedience from the Avignonese pope to produce a settlement of the Schism, the breakdown of all subsequent negotiations between the rival pontiffs, and finally the convocation, by dissident cardinals from both camps, of a general council which was to meet at Pisa in March, 1409.