Age of Empires II: The Age of Kings is a real-time strategy computer game set in the Middle Ages. It was released in 1999, and is the second main title of the Age of Empires series developed by Ensemble Studios and published by Microsoft. Due to its commercial success, an expansion pack was released; Age of Empires II: The Conquerors, followed by a Gold Edition, which bundled together the two games along with a bonus map and game matches recorded by Microsoft strategy experts.