I accidentally made a longpost on KF, so i figured i'd repost it her : just a quick overview of why the Islamic civilisation eventually declined

Islam's reliance on Jihad is an effective way to fuel conquests, since in its ideology every human on earth should either convert, pay up or die, but the problem is this tactic of zerg-rushing relies on having a very strong figurehead that can lead the conquest and rally people around it, some sort of Attila or Alexander the Great. What you quickly see happen with Islam is that they take up a lot of lands very quickly, then their leader dies, and then basically every either collapses or slows down to a crawl because the power vaccuum created ends up causing a civil war, or the hastily conquered regions (that weren't colonised yet) start yearning for independence, or the ONE thing that's supposed to keep your people united (religion, through the ummah) suffers a schism and everything goes to shit.

People think taking over a country is a big thing, but while decapitating its elite and putting yourself in their place is an impressive achievement on the surface, it means jackshit if you can't control the people, which was often what happened with the Arabs, who just formed a ruling elite that wanted little to do with the local population. Successful empires generally solve this issue either by military occupation (though this ceases to be effective once the soldiers aren't there, look at the USA in the Middle East for proof of that), by trying to insert themselves in the local culture to gain legitimacy (like the Franks in Gaul, who essentially claimed the title of consul or imperator in order to appear more legitimate to the local Gallo-Roman population) or by straight up replacing the locals through colonisation. The Arabs tried to bypass this by colonising the people using religion to replace their local culture, but the numerous schisms in Islam hindered it a lot.

They also got extremely lucky, with the Persians suffering from a hundred years of wars with the Romans, the Byzantines being taken up on multiple fronts, the Goths having a succession crisis and their lands being in general unusually productive during the time of their rise.

And with the Abbasid Revolution in the 740's, despite Islam uniting the conquered populations, everything splits apart and the empire ceases to grow, though they did grow culturally thanks to their absorption of Roman remnants in the Middle East and their conquest of Persia (both which also coincidentally formed the gateway between Europe and Asia), which guaranteed them a solid cultural base which while not originally theirs was slowly but surely assimilated into Islamic culture. That's the one big advantage with identifying with religion instead of ethnicity, it allows you to bypass race and culture and keep up the appearance of a strong and united group.

They technically managed a renaissance with the arrival of the Ottoman Turks, who took none of that bullshit and managed to keep a central authority (on top of having a much more stable empire that they built from years of steady conquests instead of zerg-rushing like iditios), but even then, as soon as that empire stopped growing, Islam just hindered them from progressing further culturally. Interesting to note is that imo the "Islamic" civilisation and the "Ottoman" civilisation are quite different ; while they share the same religion, which makes them appear similar, the latter was Turkic in character and actually a lot more Western-influenced thanks to the taking of Constantinople. In general it's quite funny because most parts of the Islamic civilisation are not Arab at all, but rather a mix of Persian, Byzantine and Turkish/Ottoman.

From the day the 19th century arrived the Ottomans and Islamic civilisation in general was already cooked ; they lost wars by the dozens thanks to their ultraconservatism and their lack of forward-thinking. Islam's a neat religion for expansionism but it doesn't really drive people to innovation or change, and its philosophy leads to stagnation without outside stimulation. Turkey itself only really got off the ground again when Ataturk brought secularism to it, though the sheer technical r-sluration of the Empire means even the unity of religion couldn't save it.

PS : i remember a particularily funny incident where Ottoman officers visited Ludwig Loewe (German manufacturer) to look into possibly buying machine guns for the Ottoman Army. The guy at the factory noted that they seemed to not give a single actual frick about their task. Here's an excerpt from an old article on the subject :

According to the correspondence, it seems obvious that Luger professionally supported and advised the Montenegrins. On July 10, 1907 he wrote to Haydukovich: "I am bound by my word to support and defend your interests and behave as being one of you." He gave detailed data about other countries' armaments asking for conspiracy of confidentiality in that regard. On December 30, 1906, he informed Haydukovich that, "Turkish Government had commissioned 50 machine guns." In the letters of May 19 and July 10, 1907 he reports that the work on finishing the Turkish machine guns were being accelerated. That weapon was 7.65mm calibre and "adopted to fit the wheeled version of sled mount M1901 that could be pulled on the wheels or carried on horseback. The mount mass was 67 kg and machine gun and carriage mass was almost 100 kg (sic), which means that the weapon was too heavy for the hilly terrains." Luger did not hesitate to mention that the "two Turkish officers responsible for receiving material were completely ignorant as to the machine guns and, in addition, they showed no interest in learning anything, but were only embarrassed because smoking in the factory was forbidden.

Really speaks as to how far behind Islamic civilisation was in the end, when the top brass of its army couldn't even be bothered when it came to the biggest military revolution of the time. Even the bloody Montenegrins were more professional.