Adoni-zedec (Hebrew: "lord of justice or righteousness") was king in Jerusalem at the time when the Israelites invaded Canaan (Joshua 10:1,3). He formed a confederacy with the other Canaanite kings against the Israelites, but was utterly routed by Joshua when he was engaged in besieging the Gibeonites . The history of this victory and of the treatment of the five confederated kings is recorded in Josh. 10:1-27. (Comp. Deut. 21:23).
The author of this article for the Easton's Bible Dictionary states that amongst the Amarna letters are some letters from Adoni-zedec to the King of Egypt, which add to the history recorded in Josh. 10. However, the only king of Jerusalem mentioned in this archive is one `Abdi-Heba (whose name translates as "servant of Heba"), who is said to have succeeded Lab'ayu . Six of his letters to the king of Egypt (EA 285-290) are included in the Amarna letters, and he is mentioned in a seventh (EA 280). Perhaps the Dictionary author saw how `Abdi-Heba complained of the raids by the Habiru, who at the time were unquestioningly identified with the Hebrews, and forced the identification.