The Byzantines were very seriously on the decline by 1400. Constantinople was a shadow of it’s former glory, and the territory it governed was not doing very well either. If they made the cut I really don’t see why Venice, Paris, Milan and Bruges wouldn’t, as they were some of the largest and richest human settlements on the planet at the time.

Al-Andalus had also been gone for hundreds of years, and by 1400, only the Emirate of Granada remained which would be very unlikely to make the list.

On a global scale Europe was a poor, irrelevant backwater that didn’t have much in the way of achievements that we mention or much pull beyond its own corner of the globe.

While they were certainly not at the height of their proportionate wealth and influence, Europe in 1400 was still one of the most significantly densely populated areas on earth, making up roughly 25% of the world’s population, with China and India each being another 25%, and the rest of the world making up the last quarter.

They made plenty of technological innovations too, improvements on horse collars, ploughs and horseshoes all originated in Europe at the time and significantly improved the life of the working population. There were also major novel advances like eyeglasses, rudders, navigational tools, compound cranks, rolling mills, glass mirrors and a host of others.

Go back to the 800s-900s and you’d be more accurate.