The Korean king Snjo (1552-1608) ruled from 1567 to 1608. His reign was marked by factional strife, serious economic and social discord, and two destructive Japanese invasions.

Snjo, formally named Yi Kong and known before his accession as Prince Hasng, was born on Nov. 26, 1552, the third son of Prince Tkhung, a younger brother of the kings Injong (reigned 1544-1545) and Myngjong (1545-1567). When Myngjong died without an heir, he gave his deathbed approval to the designation of Snjo as his successor. The 14-year-old boy took the throne on Aug. 7, 1567. For the first year of his reign the queen dowager served as regent, but when the chief officials urged that Snjo, though so young, was ready for rule, the dowager yielded, and from 1568 on the royal decisions were Snjo's.

At first it seemed that Snjo's actions might help to dissolve the political strife of the preceding 50 years, during which a succession...