Yes history is changed by those that survived it in a lot of cases, and despite the near 1500 years or so that the Roman Empire actually existed, we just seem to accept that a bunch of Goths (not the hot ones wearing hot skirts and black lipstick) destroyed the Roman empire around the 5th century, and somewhere after that a French-ish guy named Charlemagne harassed the pope. Of course the Byzantines as we call them now continued to call themselves Romans, and if a Roman of the 4th century all clad in armor were to look upon a 14th century Roman in silk and wearing a turban, it probably wouldn’t go over well. The 14th century Roman would be speaking Greek, and wouldn’t cross the street to spit on the Pope, but they were Romans, and they were the end of the Constantine Empire of Rome, which is why until the very death of the last Byzantine the city they lived in was called Constantinople.
That little peninsula at the end of Turkey though as long as it had been an obstacle to the mighty Ottoman Empire seriously is probably the only reason that Europe was able to evolve to the point that it had. Aside from Spain Europe had managed to be relatively unharmed from the caliphate. I know wah wah wah Crusades wah wah wah Israel wah wah wah, but the Crusades WERE retaliation for the caliphate and the final two Crusades were the Catholics attacking the Orthodox not the Muslims. It was the walls of Constantinople that kept the Ottoman Empire busy for a very long time. The official fall of the Roman Empire came when the walls of Constantinople finally fell, and the city was defenseless.
That itself is a tragedy of sorts. The invention of gunpowder weaponry over in China as the Ming Dynasty (yeah the vase people) finally took back the land from the Mongols’. The guns that they created which neutralized the greatest cavalry in the history of mankind, within a hundred years were creating the cannons that would break through the greatest walled city in the history of mankind. The tragedy comes in the fact that the people who were building the cannons were originally part of Constantinople, but the city had never regained its prominence after the fourth crusades, and couldn’t afford to pay them. The Ottomans were willing to pay them, and what was left over of the Roman Empire finally was destroyed in 1453 when the Ottoman Sultanate became the Ottoman Empire.
The Ottomans would go on to dominate Eastern Europe for about 450 years. By today’s standards the average American knows nothing of the caliphate which wasn’t abolished until 1924. I still haven’t figured out of that bit of history is ill regarded because the Ottomans picked the wrong side during World War 1 or because people just don’t want to admit things like caliphates exist. Of course we have a group of insane Islamists now wreaking havoc in Syria and Iraq which have proclaimed themselves a caliphate, with a leader who considers himself the caliph. The history that should be learned in all of this is not so much that there is a caliph or a caliphate, but an enduring empire of 1500 years can be completely wiped from the map, have its history completely scrambled and set aside by one of these movements. Think of what it can do with all of these countries that have yet to endure for a century or two, maybe three?