The Three Kingdoms Period of ancient Korea (57 BCE – 668 CE) is so-called because it was dominated by the three kingdoms of Baekje (Paekche), Goguryeo (Koguryo), and Silla. There was also, though, a fourth entity, the Gaya (Kaya) confederation at the southern tip of the Korean peninsula.
According to Perry Rogers, one reason the Chinese were unsuccessful in halting the opium <span>trade was because the country had come to depend on it for revenue. </span>
