The Battle of Thiepval Ridge was the first large offensive mounted by the British Reserve Army of Lieutenant General Hubert Gough during the Battle of the Somme and was designed to coincide with British Fourth Army's Battle of Morval by starting exactly 24 hours after it. Thiepval itself was a village on a spur dominating the Ancre valley, although the actual front for the Battle extended from the Schwaben Redoubt to Courcelette.
http://en.wikipedia.org/wiki/Battle_of_Thiepval