Sestertius coin, part of the “Twelve Ceasars,” bears a portrait of the ruler seen as notorious and nefarius in his ruling. The reverse features the three sisters of Caligula, as well as their names (Drusilla, Julia, and Agrippina). Appearing on the coin didn’t appear to be a good omen for the three. The Roman Empire produced many bad emperors, but Gaius, nicknamed Caligula, must be ranked among the worst. He not only murdered his pregnant wife; he also heaped public honors upon his horse. He was the great-grandson of the Emperor Caesar Augustus but unfortunately had inherited none of his ancestor’s talents. It all began in September A.D. 12 when he was born at Antium, the son of Germanicus and Agrippina. Germanicus died when Gaius was seven, but before that he had lived with his father. Growing up in army camps in Gaul, the young Gaius wore a special boot and the soldiers nicknamed him “little boots,” or Caligula. Emperor Augustus died in A.D. 14 and was succeeded by Tiberius, who...