From Halopedia, the Halo wiki
2003 saw the second and third novels, as well as Halo CE released for PC.
- April 1:
- August: The tiltrotor squadron VMX-22 was established in the United States Marine Corps. A namesake of the unit would later be a part of the UNSC Marine Corps.
- September 29: The first edition of Halo: Combat Evolved: Sybex Official Strategies & Secrets is released.
- September 30: Halo: Combat Evolved for the PC is released.
- October 28: A special edition of the Halo: Original Soundtrack is released.
- December 2: The novel, Halo: First Strike is released.