Many aspects of the ancient Olympic Games would be perfectly familiar to fans at the upcoming games in Rio de Janeiro: elite international competition, cheering crowds in the tens of thousands, events like sprints, wrestling, discus, and javelin. Then as now, Olympic contenders often spent years training with expert coaches, and victors were showered with praise and wealth.

But other elements of the ancient games would seem very strange to spectators today. It’s hard to imagine a modern Olympics featuring the sacrifice of 100 oxen, or the public whipping of athletes caught cheating, or a race in full body armor. Athletes competed au naturel, examined the entrails of sacrificed animals to see if they prophesied victory, and were rewarded only for