 Complete the following phrase:  The princes of Europe were slow in responding to the call of the pope, largely due to national rivalries. England and Frances Hundred Years War had just ended in 1453. Forces led by John Hunyadi , Captain-General of Hungary, met the Turks and defeated them at Belgrade 22 July 1456. Shortly after his victory, Hunyadi himself died of a fever. On 29 June 1456, Callixtus III ordered the church bells to be rung at noon see noon bell as a call to prayer for the welfare of those defending 