Maine was so enthusiastic for the cause of preserving the Union in the American Civil War that it ended up contributing a larger number of combatants, in proportion to its population, than any other Union state. It was second only to Massachusetts in the number of its sailors who served in the United States Navy. Joshua Chamberlain and Holman Melcher along with the 20th Maine Volunteer Infantry Regiment played a key role at the Battle of Gettysburg, and the 1st Maine Heavy Artillery Regiment lost more men in a single charge (at the Siege of Petersburg) than any Union regiment in the war.