“Improving” is a light word, medieval Arab and Persian scholars really radically transformed basic understandings from antiquity

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Hell, in the time of European history known as the “dark age” there was a whole ass Islamic golden age

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The Islamic empires and mongol trade networks (later Islamized) were also how knowledge travelled from China and India to Europe

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The fall off is crazy

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I mean without the Muslim invasions. The Byzantine Empire would probably have been able to keep it going. Same with the zoroastrian Persians. For India the Muslim invasions happened 300 years after the fall of the empire. The culture had kept its history and works. The conquests did damage local culture and inhabitants including artifacts and information with many religions in Central Asia disappearing as a result. Knowledge may have been loss but knowledge would also have been preserved

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