About 220 BC a Carthaginian spy was arrested in Rome. He had been living undetected in the city for about two years. Both his hands were chopped off, and then he was sent back to Carthage. The person who had provided the information allowing for the arrest got 20,000 heavy asses as a reward. The head money was disbursed in coins like this one: the as represented the highest denomination the Romans had at their disposal for inner-Roman payments at that time.
Since its introduction in about 280 BC, the weight of the as had been repeatedly reduced. Asses like this one – with the double-faced head of god Janus on the obverse, and a prora on the reverse – weighed about 267 grams. The total weight of the reward therefore amounted to about 5,340 kilograms of bronze.