In search of the alien 'brand'
An intriguing place to see how the possible (likely?) presence of aliens on earth dates back thousands of years is at: UFOart.com. By looking for clues in the art of primitive cultures around the world, the author has put together an intriguing collection of 'alien' depictions.
What's more interesting is the consistency with which these cultures from around the world rendered 
these beings on cave walls and in mountain rocks. The clothes worn by these figures in paintings / carvings is strikingly similar: robes with an intricate bodice around the waist. Very uniform, which is important for getting a single impression across to target audiences. Also noticeable is the offbeat colors used to render their clothes and helmets. These were very memorable to the inhabitants at that time and obviously a lot of quality pop art was born. (think McDonald's). Even though these visitors from distant planets haven't been driving their brand here for thousands of years, we still can't get enough. It's just good to see that in civilizations more advanced than ours, the marketing is too.