I was thinking about this when I was watching some Roman flick.
These people all live in a pretty warm climate and dress accordingly with light and skin revealing attire. So them not having any "pharmaceutical" or medical protection seems like it'd be a persistent issue with no solution other than to you know wear more clothes.
Was this even an issue back then?
In both the time of the Roman Empire and in the Middle Ages, it was less common than today for there to be a significant mismatch between observed skin color and predicted skin color based on UVMED (basically the amount of UV radiation required to induce sunburn). The evolution of human skin coloration, Jablonski NG, Chaplin G., J Hum Evol. 2000 Jul;39(1):57-106.
See also Figs. 3 and 4: http://faculty.washington.edu/charles/562_f2011/Additional%20Readings/Jablonski%202000.pdf
With that said, there still was sunburn even before that time. Strabo noted the Indian people were "not so mercilessly burnt." Benjamin Isaac, The Invention of Racism in Classical Antiquity, 2004.
Ancient Greeks used hats, veils, parasols and other clothing for protection, but there is little evidence for specific recommendations in Middle Ages Europe. Part of the reason could be the shorter lifespans of that time. P.U. Giacomoni, Sun Protection in Man, 2001
In Myanmar (formerly Burma) they still use Thanaka, a paste made from ground bark. It's been used in that region for centuries. Ancient Egyptians used a cream made from rice bran. People also used hats and umbrella's to shield themselves from the sun.
Info on Thanaka: http://www.southworld.net/newtest/index.php/component/k2/item/432-myanmar-%E2%80%93-thanaka-the-secret-of-beauty