After failing to take Madrid by frontal assault, General Francisco Franco gave orders for the road that linked the city to the rest of Republican Spain to be cut. A Nationalist force of 40,000 men, including men from the Army of Africa, crossed the Jarama River on February 11, 1937. General José Miaja sent three International Brigades to the Jarama Valley to block the advance. Law first saw action on February 17. After disastrous setbacks on February 27, Law had performed well on the day and was soon promoted to section leader. Two weeks later he was made commander of the machine-gun company, when his superior officer was killed. The battalion leadership was annihilated at Jarama and Law advanced fast in rank, even though there was some criticism of his performance at the attack on Villanueva de la Cañada.