Alexander IV succeeded Innocent IV as guardian of Conradin, the last of the Hohenstaufens, promising him protection; but in less than three weeks he conspired against him and bitterly opposed Conradin's uncle Manfred.P. Touron, "Alexandre IV contre Manfred," Le Moyen Âge 69 (1963), pp. 391–99. Alexander IV threatened excommunication and interdict against the party of Manfred without effect. Nor could he enlist the kings of England and Norway in a crusade against the Hohenstaufens. Rome itself became too Ghibelline for the Pope, who withdrew to Viterbo, where he died in 1261. He was buried in Viterbo Cathedral, but his tomb was destroyed during sixteenth-century renovations.
