Some people use 1492 and Columbus' arrival in America to mark the end of the middle ages.

What we do have to remember is that in May 1453 no one thought: "Goodbye middle ages and hello early modern age!" The reason we use those dates are because large changes happened.

• 1453 ==> Constantinople and the Eastern Roman Empire falls. The ERE which had been there since ~300 AD collapsed (well it had been crumbling for a while) after the Ottoman Empire took their capital. If we look at it from our perspective we see a large change which is why it's used as a end date for the middle ages.

• 1492 ==> Columbus arrives in America and discovers a whole new continent previously unknown to Europeans (the major powers at that time). A new age of colonization and imperialism will begin soon. So lots of changes.

Of course these aren't the only things that happened but they were major occurrences which "changed history", so to speak.

Hope this helped you understand a bit. Also, mods, if this answer isn't good enough for this sub feel free to delete it.

the end of the Middle Ages and the beginning of the Renaissance

Just to address this specifically...the fall of Constantinople had really nothing to do with the Renaissance, and nobody will tell you the Renaissance began in 1453. Our major eras of European history go Ancient-Medieval-Early Modern, and the Renaissance is a period that bridges the late medieval and early modern eras.

Virtually all such dates are random. People, especially in previous centuries, really want to order history into intelligible segments. And also, it helps when teaching people (children) history to have events and movements clearly defined.

But I couldn't tell you off a single case where once you really dig into the modern academic understand these neat clean divisions hold up. The renaissance too, if I remember my courses correctly, is considered to have started a century earlier in Italy and a century later in England. There's a point to talking about the Renaissance as a period distinct from Medieval times, but not to trying to cleanly delineate when one ended and the other begins.

That is not to say the Fall of Constantinople was inconsequential. But we've got some great Byzantine experts here so I'll defer to them to answer on the actual effects of Constantinople's end on Western European culture.

I think a reasonable argument can be made that the fall of Constantinople marked the end of antiquity. This was a Roman culture which had existed, albeit around a few different locations, since right back to the height of the power of the Greek city states. I think that it makes sense to count the time whilst the Byzantine empire was still hanging on as 'late antiquity'.

After the fall of Constantinople (along with the end of the Hundred Years War, but Constantinople's the big one that's remembered), you have the fall of a significant power from the scene. Even though the Byzantine 'empire' had, for some time, been essentially just Constantinople, it was still of some importance from its sheer heritage and age. It still carried the weight of that reputation, if in an altered form. For instance, I think one of the biggest pieces of evidence here is that the Ottoman sultans toyed with including 'kayser' or maybe 'basileus' as part of the sultan's full title. There was still power in those names, even if the state itself had lost real power long ago.

I think the fall of this ancient power really makes historians take stock of things. You look around and you see the rise of the great Sunni state, the Ottoman empire, which lasts for 600 years or so. You see the change of warfare from cavalry (which it was by this point) to gunpower weaponry. You see that the world is moving into more recognisable forms of states.

I think these things were absolutely developing before 1453, but I think that whilst the Byzantine empire still exists it colours our sense of what's going on. There's still that continuous link to the ancient past. The fall of Constantinople cuts that link and gives us a wake-up call that history is really moving on, into something which is beginning to resemble the modern era.

Follow up question: Would 1453 also be considered a Watershed moment because of the end of the Hundred Year's War between England and France, and the dawn of new relations that came with that?