2001

In 2001, the first entries into the Halo universe were released.

May
May
 * Microsoft acquires Ensemble Studios.

August
August 15
 * The approximate origin date for the Beta 1749 build of Halo: Combat Evolved.

October
October 30
 * The novel Halo: The Fall of Reach is released.

November
November 15
 * The Xbox console and the video game Halo: Combat Evolved are released in North America.
 * Halo begins...