Antipope John XXIII

Antipope of the Pisan party (1400-15), born about 1370?; died [[November 22], 1419?.

Cardinal Baldassare Cossa was one of the seven cardinals who, in May of 1408?, deserted Pope Gregory XII, and, with those belonging to the obedience of Pope Benedict XIII, convened the [Council of Pisa]?, of which Cossa became the leader.

Do not confuse with Pope John XXIII, who convened the Second Vatican Council.