São Tomé and Príncipe (often called just "São Tomé" for short) is a small island nation off the Atlantic coast of Central Africa, located in the Gulf of Guinea, straddling the Equator, west of Gabon. Discovered and claimed by Portugal in the late 15th century, the islands' sugar-based economy gave way to coffee and cocoa in the 19th century -- all grown with plantation slave labor, a form of which lingered into the 20th century. Although independence was achieved in 1975, democratic reforms were not instituted until the late 1980s, and the first free elections were held in 1991.