While UV rays can cause skin cancer, because skin cancer usually affects people after they have had children, it likely had little effect on the evolution of skin color because evolution favors changes that improve reproductive success.
The only problem was that I couldn't remember where I had heard that. In fact, I wasn't all that sure that I was right. I know that the Roman Empire lasted rougly 500 years but how about the Egyptians, the Chinese, the Ottomons, etc. I thought that it would be interesting to explore different empires and see how long they lasted. In another article, I talk about the definition of civilization..
The Holy Roman Empire had survived over a thousand years when it was finally destroyed by Napoleon and the French in 1806.t may not have been holy or Roman or an empire, as Voltaire remarked, but whatever it was, it had survived for more than a thousand years since the coronation of Charlemagne in the year 800.