The Combined Fleet
Napoleon's attempted invasion of Britain had failed and the French Navy was scattered. Villeneuve had escaped from Toulon, joined with Spanish forces, and sailed to the West Indies. On his return, he did not sail northwards to free Ganteaume in Brest as planned, but went south and slipped into Cadiz.
When the Combined Franco-Spanish Fleet emerged from Cadiz on 19 October 1805, it headed south towards the Mediterranean. Villeneuve had been instructed to attack Naples, in order to divert Austrian forces towards Italy and disrupt their campaign in central Europe.
The Combined Fleet numbered 33 ships of the line – 15 Spanish and 18 French – and included the massive Santísima Trinidad. Despite their numerical superiority, they suffered from sickness and low morale. Both Villeneuve and the Spanish commander, Gravina, knew that they were facing a formidable enemy.