He was commander during the Battle of the Somme , the battle with one of the highest casualties in British military history , the Third Battle of Ypres , and the Hundred Days Offensive , which led to the armistice in 1918 .
Most notably , he was commander during the Battle of the Somme , the Third Battle of Ypres and the Hundred Days Offensive , which led to the German surrender , in 1918 .