A March is music with a strong simple duple rhythm written to accompany a marching group, (eg soldiers), often the band marches with the troop. Faster marches are often in compound duple time, i.e.6/8, slower marches are usually in 2/4 or 4/4 time.
While drums and pipes have probably been used to accompany marching soldiers since Roman times, the modern repertoire starts with the French revolution, when Rouget De Lisle composed la Marseillaise. The 19th century inspired many composers to write marches, often expressing patriotic and nationalist sentiments. In the USA John Philip Sousa, as bandmaster of the US Marine band, composed some of the most famous and widely played marches ever written. His marches were composed to be played by a military band on the march.
Marches scored for a full symphony orchestra have been incorporated into symphonies, piano music and many operas, by classical and romantic composers. Famous examples include the Triumphal March from Verdi's Aida, the march from Le Prophete by Meyerbeer, Schubert's Marche Militaire, and Bizet's Toreador's March from Carmen