Despite what has been written in many books and magazine articles, the Ulster Division was not formed overnight by an en bloc enlistment from the Ulster Volunteer Force and Young Citizen Volunteers, nor were the YCV the youth wing of the UVF, as some believe. Despite the surge of patriotic enlistments on the outbreak of war, by December 1914 there was still a shortfall of 1,697 men, the majority of these shortages being in the divisional troops, not the infantry brigades. It was proving difficult to fill the ranks of the Royal Army Medical Corps, Army Service Corps, Cyclist Company and Royal Engineers, in fact any unit that required a degree of mechanical skill, however small. Despite these initial difficulties the Division sailed for France in October 1915 and by the following June had gained ample experience in trench life. However it was 1 July 1916, that would change the Division from naive volunteers into battle hardened warriors and ensure their undying fame. This study follows the division from its creation through to disbandment, drawing extensively on unpublished materials, official documents and newspapers. In doing so it provides an up-to-date picture of this famous and important formation.