Eiso (永祚) was a Japanese era name (年号, nengō,, lit. "year name") after Eien and before Shōryaku. This period spanned the years from August 988 through November 990. The reigning emperor was Ichijō-tennō (一条天皇).
Eiso (英祖, Chinese pronunciation "Yingzu") (1229–1299), was a king of the Ryūkyū Islands.
Eiso was a member of the Tenson family; and he is also known as the first of the Eiso Lineage of Ryukyuan monarchs. He served as Regent from 1235 to 1260, and afterwards as king, succeeding Gihon and reigning until his death in 1299.
Eiso's reign is generally seen as one of great growth for the fledgling Okinawan principality. Eiso instituted a variety of tax and land reforms, and the nation recovered from famines and other problems which plagued the previous reigns. Several outlying islands, including Kumejima, Kurama, and Iheya, came into the sphere of Okinawan control, and began sending tribute in 1264. An envoy was sent to Amami Ōshima in 1266, though it was not until much later that Okinawa's sphere of control would be expanded to include the Amami Islands. In short, Eiso's reign saw the establishment of many governmental institutions, and helped to set the foundation for the structure of the government of the following centuries.