The Pride and the Passion

The Pride and the Passion is a movie starring Cary Grant, Frank Sinatra, and Sophia Loren. During the Napoleonic Wars, a British captain is sent to Spain to help prevent the French from stealing a powerful cannon.
During the Napoleonic Wars, when the French have occupied Spain, some Spanish guerrilla soldiers are going to move a big cannon across Spain in order to help the British defeat the French. A British officer is there to accompany the Spanish and along the way, he falls in love with the leader's girl.