Rome (papal capital)

Timeline

1. 1451–1455Rome, Vatican · RomePope Nicholas V (pontificate 1447–1455) pursued an ambitious rebuilding program for Rome between 1451 and 1455: expanding the Vatican palaces, repairing the old St. Peter's Basilica and planning a new church, while founding the Vatican Library and acquiring large numbers of Greek and Latin manuscripts, making Rome a major center of European humanist scholarship.
2. 1453–1456Rome · LazioIn May 1453 the Ottoman Empire captured Constantinople, deeply shocking the Roman curia. Nicholas V promptly called for organizing a crusade, but European states responded only weakly. His successor Callixtus III (1455–1458) made opposing the Ottomans the top priority, sending envoys to the various kingdoms in 1456 to negotiate; the Battle of Belgrade (1456) temporarily halted further Ottoman expansion in the Balkans.
3. 1458–1460Rome · LazioPius II (pontificate 1458–1464, born Aeneas Silvius Piccolomini) was a humanist scholar turned pope; after accession he actively promoted Rome's construction and diplomacy, convening the Congress of Mantua (1459) to negotiate an anti-Ottoman alliance. Under his leadership Rome was both the spiritual authority of the Christian world and a diplomatic hub gathering ambassadors and scholars from across Europe.