This means, ladies and gentlemen, that gears go back quite a ways in the Mediterranean and Europe. The item pictured above is called the Antikythera mechanism and is believed to have been used in an astronomical calculator. If you read the article, you’ll find references to ancient Greek automata as well. It’s not enough to make claims about the Ancient Robots, but it is certainly enough to inspire!
Costume-wise, it also illustrates the fact that, as I said above, gears are a simple machine. They require very little in the way of technology- gears could be composed of wood, stone or metal (though with various advantages and disadvantages to each material). If you have a culture known for its tinkering or engineering ability, it could very well have gear technology- and thus, possibly, gears as symbols or fashion. Work with the game staff and see what you can put together. If you design something particularly fantastic, maybe you’ll get this medal:
Or start searching Etsy to make your own.