How does the army know to cheer for Longstride?

In Robin-Hood(2010) Robin has assumed Robert Locksley's identity and position in order to help Walter, Marshall, and Marian. At no point does he ever reveal his true identity to anyone that doesn't already know it(Allan, John, Will, Marshall, Marian, & Walter), Godfrey simply knows that he isn't Robert Locksley. However, after the climactic battle, the army begins chanting the name Longstride since he led them in battle. Maybe half a dozen people know Robin's true identity and even less know who his father was.

How does the army suddenly know he's Robin Longstride and to cheer the name Longstride?