Calixtus III, Callixtus III, or Callistus III, 1378–1458, pope (1455–58), a Spaniard (b. Játiva) named Alonso de Borja or, in Italian, Alfonso Borgia; successor of Nicholas V. He acted as arbitrator between his friend Alfonso V of Aragón and the papacy, and for this he was made a cardinal (1444). Calixtus was elected soon after the fall of Constantinople, and he promptly proclaimed a crusade against the Turks. He spared nothing to aid John Hunyadi, who won a victory with St. John Capistran at Belgrade (1456). In 1457, Calixtus turned to Scanderbeg, in Albania, sent him money, and named him captain general of the crusade. Calixtus' reign was embittered by a quarrel with Alfonso, who expected returns, notably the march of Ancona, for his friendship. The pope would not give away church lands and resented Alfonso's failure to help the crusade. Calixtus' nepotism gave the Borgia family its position in Italy. Calixtus was, like other Borgias, an able administrator. He was succeeded by Pius II.
"Calixtus III." The Columbia Encyclopedia, 6th ed.. . Encyclopedia.com. (February 23, 2018). http://www.encyclopedia.com/reference/encyclopedias-almanacs-transcripts-and-maps/calixtus-iii
"Calixtus III." The Columbia Encyclopedia, 6th ed.. . Retrieved February 23, 2018 from Encyclopedia.com: http://www.encyclopedia.com/reference/encyclopedias-almanacs-transcripts-and-maps/calixtus-iii