On July 1, 1916, the British Expeditionary Force (bef) launched an offensive in the Somme region of France. Supported by some French units, the aim was to break through the German defensive lines and take pressure off the French Army. With German victories in the east, the failure of the Gallipoli campaign in 1915, and the battle of Verdun raging in the south, the Entente Alliance sorely needed a victory. Field Marshal Douglas Haig commanded the bef and planned the attack. The frontal attack proved to be disastrous, with the British losing 20,000 men in the first day. At the end of the four-month battle, 1.5 million soldiers on both sides had been killed or wounded. The British advanced only six miles. Despite the tremendous losses, the courage and steadfastness of the bef became legendary. The legacy of the battle would send shock waves throughout the fabric of British society.