Mametz Wood was one of the bloodiest battles of World War One. As part of the first Battle of the Somme in 1916, soldiers of the Welsh division were ordered to take Mametz Wood, the largest area of trees on the battlefield.
The 38th Welsh Division lost 4,000 men during the attack which lasted five days.
The poet Owen Sheers grew up in Wales and wrote the poem in 2005 as he felt their bravery and sacrifice was never really acknowledged