15 December 1899
During Anglo-Boer War 2, the British troops under General Redvers Buller launched a frontal attack in the Battle of Colenso with the intention to relieve the besieged town of Ladysmith. This purpose was not realised and as a result the British lost over 1,100 men, including Lieutenant Freddy Roberts, only son of Field-Marshal Lord Frederick Roberts. Eight Boers died and thirty were wounded. This third straight defeat of British troops, which began at Stormberg on December 10, brings the Black Week to an end.
References

SA National Museum of Military History. (1999). Anglo-Boer War 1899-1902, Johannesburg: The Museum.|Wallis, F. (2000). Nuusdagboek: feite en fratse oor 1000 jaar, Kaapstad: Human & Rousseau.