From what I was able to tell after a quick internet search, there were 6 card back variations, however 1 of them was only known to be used in series 1. Series 1 was labeled Heroes of History, series 2 Men of History, apparently.

One of my collecting goals for 2013 was to get at least one Tobacco card. I achieved that goal on January 17th, 2013 when I aquired the Julius Caesar card from this collection. It is, however, bent (which I knew going in) which leads to the somewhat uneven scan that is posted to the Database.