The Bronze Star was originally established in 1944 to recognize the unique sacrifices of infantry soldiers during WWII. However, the award was quickly expanded to include members of all the Armed Forces.  The Bronze Star can be awarded for both valor and meritorious service.  When awarded for valor, a small bronze "V" device is attached to the ribbon.

The Bronze Star Medal was established by Executive Order 9419, 4 February 1944 (superseded by Executive Order 11046,
     24 August 1962).

        a.Authorization. E.O. 11046, 24 August 1962
        b.Eligibility Requirements
             1.Awarded to any person who, while serving in any capacity with the Armed Forces of the United States,
               distinguishes himself after 6 December 1941, by heroic or meritorious achievement or service, not involving
               participation in aerial flight.
                  a.while engaged in an action against an enemy of the United States;
                  b.while engaged in military operations involving conflict with an opposing foreign force; or
                  c.while serving with friendly foreign forces engaged in an armed conflict against an opposing armed force in
                    which the United States is not a belligerent party.
             2.To justify this decoration, accomplishment or performance of duty above that normally expected, and sufficient to
               distinguish the individual among those performing comparable duties, is required, although less than the
               requirements for the Silver Star or the Legion of Merit. Minor acts of heroism in actual combat, single acts of
               merit or meritorious service connection with military or naval operations may justify this award.
        c.Combat Distinguishing Device. The Combat Distinguishing Device may be authorized.

Information and image provided by:
    The Marine Corps Wives Web Site