The royalist expeditionary navy that would raid San Lorenzo comprised eleven ships of varying sizes, two hundred and fifty soldiers and fifty sailors. They moved into the Paraná through its tributary, the Paraná Guazú River, slowed down by headwinds. The Second Triumvirate promoted José de San Martín to colonel and instructed him to follow them with the Regiment of Mounted Grenadiers and stop the raids. San Martín was influenced by Napoleonic warfare and trained the regiment with the most recent military techniques used in the Napoleonic Wars.