Among all the Korean dynasties, the Koryo dynasty (918-1392) was the first to have contact with the Western world. It was from these interactions that the current appellation of "Korea" was derived from the Koryo name. The Koryosa, or the History of Koryo, is one of the most significant historical texts on the Koryo Dynasty of the Korean peninsula. As the principal surviving history, the Koryosa elucidates the politics, society, economy, culture, and key figures of this period. Although the Koryosa was compiled during the Choson dynasty (1392-1910), much of the known information about Koryo is contained within this text, making it the primary text for understanding 500 years of premodern Korean history, culture, and civilization. This translation is the first, full-length, English-language translation of the introductory section of the Koryosa and the first ten volumes of the annals of the kings, beginning with the dynastic founder, T'aejo Wang Kon (r. 918-943) to the fourteenth monarch, Honjong (r. 1095). The nearly two hundred years of Koryo history encompassed within the first ten volumes of the annals provides invaluable insight into the birth and development of Koryo state and society, as well as the rituals and practices of warfare, diplomacy, and international relations with neighboring territories, including the Khitan, Jurchen, and Song China. The wealth of information has been integral to knowing Korea's past, offering lessons from history that are relevant to understanding modern-day Korea. Made readable to an English-language audience, this translation will interest researchers across East Asian history, and of various fields including religion, philosophy, and culture.