In early 63 BC, Mithridates the Great, king of Pontos, who ruled a territory that included most of the Black Sea coast, was in residence at his palace at Pantikapaion, just north of the sea. For thirty years he had been fighting the Romans for dominance in Asia Minor and beyond, and although he had won numerous victories, the overall trajectory was one of steady defeat for the king as Roman power spread to the east. He had been forced to abandon his traditional capital of Sinope, on the south shore of the sea, and retreat to the farthest corner of his kingdom at Pantikapaion, one of the most remote cities of the Greco-Roman world, where winters were unimaginably cold and the barbarian threat was ever present. Many of his allies and much of his family had abandoned him. Although he planned an invasion of Italy by going up the Danube and south through the Alps, imitating his famous predecessor Hannibal, he devoted most of his time to botany and pharmacology, in the long-standing tradition of scholarly royalty. But eventually he realized that he had no other options, and thus asked a bodyguard to kill him. Thus ended the career of one of the most remarkable leaders of classical antiquity, the man whom his younger contemporary Cicero called “the greatest king since Alexander [the Great].”...