Well, I suppose it was "great" in the sense of having a profound effect on European history. From what little I know, it seemed to mark the end of any hope Napoleon had for invading Britain.
Should the victory be credited to Nelson, or the quality of the Royal Navy? Some of both, I would think. History tells us that Nelson had often defeated Bonaparte's ships.
LinkQUOTE
The four years from 1797 to 1801 were a time of spectacular success and popularity for Nelson. He ensured the defeat of the Spanish fleet at Cape St. Vincent near Gibraltar on 14th February 1797 and he was promoted to Rear Admiral. He defeated Napoleon's fleet in Egypt at the Battle of the Nile on 1st August 1798, Napoleon himself having to flee from Egypt as a refugee!
. . .
After several abortive attempts at diplomacy with Napoleon, Nelson was asked to confront the French and Spanish fleets which had managed to unite and take refuge in the harbour at Cadiz in Spain. On 21st October 1805 Nelson ordered his fleet of twenty seven ships to attack the opposing enemy fleet of thirty-three ships. As the fleets approached each other Nelson had the thirty-one flags hoisted which signalled to the rest of the fleet the famous message 'England expects that every man will do his duty'. After crippling the French flagship Beaucentaure the Victory sailed towards the Redoutable. There were groups of snipers in the rigging of this ship who proceeded to fire round after round at the deck of the Victory. Nelson was one of those hit; the musket round penetrated his shoulder, hit his lung and lodged near his spine. Nelson survived the battle, acknowledging the British victory, but he died soon afterwards.
(respectfully submitted by a fan of Horatio Hornblower)