On 1 November, the advancing Austro-German forces completed a bridgehead over the River Tagliamento with the Italian army in full retreat and Venice, seemingly, within their grasp. Having personally retreated to the safety of Padua, the Italian Chief of Staff, Luigi Cadorna, ordered the Italian forces to withdraw a further 20 miles (32 km) and to regroup west of the River Piave. On 9 November, he was replaced by General Armando Diaz, who was offered Allied support. However, the Austro-German offensive was beginning to overrun its own supply lines and the advancing forces of the Central Powers were beginning to weaken. When they resumed their advance, they were repulsed by the formidable defenses of the fortress at Monte Grappa, resulting in the end of the offensive. The Italians had suffered over 300,000 casualties, of which over a quarter of a million were taken prisoner. In response, Britain and France contributed eleven divisions as reinforcements to avert Italy’s collapse.