I have a vague idea, not for a detailed timeline but for an entertaining map, of absolutist land powers of rival religions backing the naval power small mercantile states of the "opposing" religion. So European Christian landpowers relying on Swahili/Zanzibari/Omani Muslim naval power city-states/small sultanates to bypass the Muslim land powers in order to trade with the Far East. Muslim land powers (maybe a Persian Empire and whoever controls most of the Arab lands whether Turkish in ruling class or some other group) relying upon European merchant republics as middlemen between them and the markets of Christian Europe.
My POD right now is the Roman Exarchate of Africa being converted not crushed by the early caliphates, with Carthage not being reduced to rubble in 682. This still allows for familiarish little Christian states with strong merchant navies to arise from the Roman Exarchate of Ravenna, such as some form of Venice.
Keep Egypt from falling into the hands of a Muslim land power or becoming a power capable of unifying North Africa itself, and you have Omani/Swahili/Zanzibari traders getting their good overland from the Red Sea to Alexandria and to all the alternate Muslim small naval power sultanates in this alternate North Africa.
Would this POD keep eventually Christianized Scandinavians from establishing river trade routes and city-states/small states from the North Sea through Europe to the Black Sea and Caspian?
My POD right now is the Roman Exarchate of Africa being converted not crushed by the early caliphates, with Carthage not being reduced to rubble in 682. This still allows for familiarish little Christian states with strong merchant navies to arise from the Roman Exarchate of Ravenna, such as some form of Venice.
Keep Egypt from falling into the hands of a Muslim land power or becoming a power capable of unifying North Africa itself, and you have Omani/Swahili/Zanzibari traders getting their good overland from the Red Sea to Alexandria and to all the alternate Muslim small naval power sultanates in this alternate North Africa.
Would this POD keep eventually Christianized Scandinavians from establishing river trade routes and city-states/small states from the North Sea through Europe to the Black Sea and Caspian?