Warcraft III: The Frozen Throne is an expansion pack of Warcraft III: Reign of Chaos developed for Microsoft Windows, Mac OS and Mac OS X by Blizzard Entertainment. Released in stores worldwide in multiple languages beginning on July 1, 2003, it details Arthas' transformation into the Lich King, Illidan's awakening of the naga, the conversion of the blood elves, the breakdown of Horde-Alliance relations in Kalimdor, and more. The Frozen Throne takes place approximately one year after Warcraft III: Reign of Chaos, whilst World of Warcraft takes place three years after the events detailed in The Frozen Throne.