I'm interested in creating a timeline in which the Republic of Venice, instead of slowly declining over its last centuries, thrives and becomes a dominant power in Europe. To start, three differences seem necessary by the mid-1400s:
- The power of the Ottoman Empire should be greatly reduced, so Venice can expand its holdings in Dalmatia and Greece, rather than fighting costly and futile wars to defend them. Ideally, they fail to capture Constantinople in 1453, (it might also be interesting if they took Constantinople but still remained only a regional power, destroying Genoese trade while maintaining relations with Venice, but I think this would be less plausible/cause complications to the other two points)
- The circumnavigation of Africa should be greatly delayed, so there is no alternate route to Asian trade and Venice can retain control over trade from the East.
- The discovery of America should also be delayed as much as possible, since this would eventually make control over Eastern trade less relevant, and shift power towards Western European nations in a better position to colonize.
I think I've found a historical figure who could plausibly affect all of these: Infante Dom Pedro, middle son of King João I of Portugal. In OTL, D. Pedro traveled extensively through Europe, including (apparently) meeting with Sultan Murad II, a visit to Constantinople in 1424, where he was struck by how inevitable the fall of the surrounded city seemed, and a trip to Venice in 1428, where he was presented gifts of Marco Polo's book and Venetian maps of the world and of trade routes in the East. He then returned home and gave these gifts to his younger brother Henrique, better known as Henry the Navigator. So, with some small changes, we could plausibly see:
- Henry the Navigator is no longer as inspired or as able to fund explorations around Africa. Portuguese sailors never learn the Volta do Mar.
- In OTL, interest by the Portuguese in exploration prompted contact between Fernão Martins, a consult of the King, and Florentine astrologer Paolo dal Pozzo Toscanelli. Toscanelli's reliance on incorrect maps and flawed methodology leads him to believe it is possible to reach the coast of Asia in a reasonable amount of time by sailing West, and he sends this proposal and a map to Portugal. Later, this encouraging letter and map would be acquired by Christopher Columbus; without early Portuguese interest in exploration, Columbus never receives this letter and map, and is quicker to give up his idea for a westward voyage.
- King João II, grandson of D. Pedro, cited him as his major influence in OTL, and renewed exploration of Africa and Asia; instead, Portugal doesn't round the Cape of Good Hope by 1488, and Pedro Álvares Cabral doesn't attempt a Volta do Mar to round Africa and inadvertently discover Brazil in 1500.
All of which is good fodder for a purely "America isn't discovered" AH, but what about the Ottomans? I've found a couple of sources for facts about D. Pedro's trips, but the mention of his meeting with Murad II is only from Wikipedia, and there's no more info there. An Ottoman failure in 1453 would not only help Venice, but bolster the rest of the scenario (without the fall of Constantinople, there's much less interest in exploration, no Romanus Pontifex bull, etc.)
So: what could Pedro have done or not done at that meeting? Could he have affected Murad II's thinking in such a way that he'd later make a fatal error while besieging the Balkans? Or that he'd be even more firm in his refusal to return and lead the Ottoman armies at Varna? (Or just die at Varna?) And what would be the best way for him to have not ended up with those Venetian maps, and less concerned about the fate of Byzantium? Let me know any ideas/thoughts!