On 11 February 1937, a Nationalist brigade launched a surprise attack on the André Marty Battalion (XIV International Brigade), killing its sentries silently and crossing the Jarama. The Garibaldi Battalion stopped the advance with heavy fire. At another point, the same tactic allowed the Nationalists to move their troops across the river. On 12 February, the British Battalion, XV International Brigade took the brunt of the attack, remaining under heavy fire for seven hours. The position became known as "Suicide Hill". At the end of the day, only 225 of the 600 members of the British battalion remained. One company was captured by ruse, when Nationalists advanced among their ranks singing "The Internationale".