Oath-taking, before Augsburg (1808)
Oath-taking, Champ de Mai (1 June 1815)
Oath-taking, Champ de Mars (5 December 1804)
Oberhausen, Battle of (27 June 1800)
OcaƱa, Battle of (19 November 1809)
On n'passe pas -- Battle of Ebersberg evening (3 May 1809)
Oporto, Battle and Taking of (29 March 1809)
Oporto, fall of (11 May 1809)
Orthez, Battle of (27 February 1814)
Osterode, Napoleon at (February-March 1807)
Ostrowno, Battle of (25 July 1812)