The Battle of Copenhagen (Danish: slaget på Reden) was an engagement which saw a British fleet under the command of Admiral Sir Hyde Parker fight and strategically defeat a Danish-Norwegian fleet anchored just off Copenhagen on 2 April 1801. Vice-Admiral Horatio Nelson led the main attack. Copenhagen is often considered to be Nelson’s hardest-fought battle which was won much to his credit. The battle is perhaps best known for his famous ‘mistake’ to miss Admiral Parker’s orders using the telescope with his wrong eye.
At 1:00 pm Admiral Parker held the back rank in order to engage in a flank attack. He would have been able to see little of the main battle owing to gun smoke, though he could see the signals on the three grounded British ships, with the Bellona and Russell flying signals of distress and the Agamemnon a signal of inability to proceed. Parker was under the impression that Nelson might have fought to a stand-still at the frontine and was unable to retreat without orders. Retreating without orders was unforgivable for a British Naval officer since the Articles of War demanded that all ranks do their utmost against the enemy in battle.
At 1:30pm Parker told his flag captain, “I will make the signal of recall for Nelson’s sake. If he is in condition to continue the action, he will disregard it; if he is not, it will be an excuse for his retreat and no blame can be imputed to him.” Nelson ordered that the signal be acknowledged, but not repeated. Supposedly he turned to his flag Captain, Foley, and said “You know, Foley, I only have one eye — I have the right to be blind sometimes,” and then, history would have us believe that while holding his telescope to his blind eye, Nelson said “I really do not see the signal!”. Nelson’s second-in-command, Rear Admiral Thomas Graves, repeated the signal, but in a place invisible to most other ships while keeping Nelson’s ‘close action’ signal at his masthead. It remains unclear whether Rear Admiral Graves used this cloak and dagger approach on Nelson’s orders, deliberately flying the signal flags to retreat in a place where almost no other ship could see. Only captain Riou, who could not see Nelson’s flagship, the Elephant, followed Admiral Parker’s signal to retreat. Riou withdrew his force, which was then attacking the Danish Tre Kroner fortress. Riou exposed himself to heavy fire and was killed in the retreat.
However, it was at this time that the battle swung decisively to the British, as their superior gunnery took effect. The guns of the dozen southernmost Danish ships had started to fall silent owing to the damage they had sustained, and the fighting moved northward. According to British eyewitness accounts, much of the Danish line had fallen silent by 2pm.
The decisive crush was made at the time when Nelson ‘ignored’ Admiral Parker’s signal. Since then The Battle of Copenhagen would be mentioned in history as the naval battle that was won because Nelson ‘held the telescope to his wrong eye’ and in doing so missed Parker’s signal.