Crimean War
Soon after, a Russian cavalry movement was countered by the Heavy Brigade, who charged and fought hand-to-hand until the Russians retreated. This caused a more widespread Russian retreat, including a number of their artillery units. When the local commanders failed to take advantage of the retreat, Lord Raglan sent out orders to move up. The local commanders ignored the demands, leading to the British aide-de-camp personally delivering a quickly written and confusing order to attack the artillery. When the Earl of Cardigan questioned what they referred to, the aide-de-camp pointed to the first Russian battery he could see – the wrong one.

Q: Who countered the Russian cavalry's movement?
Heavy Brigade