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 Roman Empire split into a Western Roman Empire and an Eastern Roman Empire in 395 CE. The Western Empire ended in 476 CE. The Eastern Empire, or Byzantine Empire, ended in 1453. Depending on how you define the Roman Empire: The united empire lasted 426 years The Western Empire lasted a further 81 years, for a total of 507 years The Eastern Empire lasted a further 1058 years after the split, for a total of 1484 years.