The Trumpet-Major

Anne Garland is pursued by three suitors: John Loveday, the eponymous trumpet major in a British regiment, honest and loyal; his brother Bob, a flighty sailor; and Festus Derriman, the cowardly nephew of the local squire.
The novel is set in Weymouth during the Napoleonic wars; the town was then anxious about the possibility of invasion by Napoleon. Of John Loveday fights with Wellington in the Peninsular War and and his brother Bob serves with Nelson at Trafalgar.