Black Week refers to the week of 10–17 December 1899 during the Second Boer War, when the British Army suffered three devastating defeats by the Boer Republics at the battles of Stormberg, Magersfontein and Colenso. In total, 2,776 British soldiers were killed, wounded and captured during this period. The events were an eye opener for the government and troops, who had thought that the war could be won very easily. British units were armed with then-modern magazine-fed small arms, the .303 caliber Lee–Enfield and Lee–Metford, and breech-loading field artillery. Boers were armed with the 7mm 1893 Mauser rifle, and fielded German-built breech-loading field artillery. The British, however, were accustomed to fighting tribal wars with tactics more suited to the Napoleonic era, and had no tactical doctrine in place to fight against a foe also armed with the same modern weapons, and suffered accordingly. With new, modernized troops came new tactics; only a few months after Black Week, one of the main British cavalry divisions led a flanking march that ended with a victory. Besides equipping the cavalry with rapid-firing rifles instead of lances, the new British military doctrine also started using artillery as a defensive unit of the army, and saw innovation in the use of machine guns. These new volunteers served as a "new face, untainted by defeat and accusations of defeatism…to breathe life back into the campaigns and restore hope at home." Other changes enacted by the British immediately following the Black Week disaster were the mobilization of two more divisions, the calling up of the army reserves, raising a force of mounted infantry for better mobility, and most importantly by sending volunteers from home overseas which added more than one hundred thousand additional troops by the end of the war. Political situation During Black Week, the British War Office assumed the leading role while the Colonial Secretary stepped back in the cabinet and the Boer War raged on. The reverses and humiliations for the Army hit the London government hard. Chamberlain was eclipsed in Cabinet during December 1899. Ironically Chamberlain had initially been offered the War Office by Lord Salisbury when the government was formed in 1895; had he accepted he would have been at the War Office dealing with the difficulties in the Cape. Arthur Balfour was acting Prime Minister, and Lord Lansdowne, Secretary for War. Lord Salisbury, grieving at Hatfield for his dead wife, was