Preventing the advent of European colonialism is a pretty common topic of discussion here- but how about, rather then prevent it, merely delaying it slightly, by 50-100 years?
Given how the Portuguese exploration was supported by the Portuguese crown, the pace of their exploration was heavily dependant on the government's willingness to fund it- financial troubles in Portugal, or a monarch with different priorities, could plausibly delay the circumnavigation of Africa by a few decades or more.
As for the Americas- the previous POD is probably enough to butterfly Christopher Columbus's existence. Without any Coloumbus analogue, the most likely beginnings of European colonisation in America are Portuguese sailors stumbling upon the Brazilian coast and European fisherman discovering the New Foundland fisheries. Given how far these areas are from mesoamerica, I don't think it's at all implausible to delay encounters with Europe by around a century.
The implications for the Americas are quite drastic-old world diseases are likely to have devastated the civilised centres of Mesoamerica and the Andes well in advance of European arrival, and perhaps have developed some degree of herd immunity and re-established some form of stable political order after the initial chaos.
The implications for the Middle East and Asia are another matter. Delaying the redirection of trade routes could have some pretty serious implications, as it would in turn delay the economic decline of the Ottomans. Possibly could be enough to make the difference when they sieged Vienna?
I don't have enough knowledge about the Asian polities of the time to speculate about what the delay would mean for them...
Given how the Portuguese exploration was supported by the Portuguese crown, the pace of their exploration was heavily dependant on the government's willingness to fund it- financial troubles in Portugal, or a monarch with different priorities, could plausibly delay the circumnavigation of Africa by a few decades or more.
As for the Americas- the previous POD is probably enough to butterfly Christopher Columbus's existence. Without any Coloumbus analogue, the most likely beginnings of European colonisation in America are Portuguese sailors stumbling upon the Brazilian coast and European fisherman discovering the New Foundland fisheries. Given how far these areas are from mesoamerica, I don't think it's at all implausible to delay encounters with Europe by around a century.
The implications for the Americas are quite drastic-old world diseases are likely to have devastated the civilised centres of Mesoamerica and the Andes well in advance of European arrival, and perhaps have developed some degree of herd immunity and re-established some form of stable political order after the initial chaos.
The implications for the Middle East and Asia are another matter. Delaying the redirection of trade routes could have some pretty serious implications, as it would in turn delay the economic decline of the Ottomans. Possibly could be enough to make the difference when they sieged Vienna?
I don't have enough knowledge about the Asian polities of the time to speculate about what the delay would mean for them...