Since May 1706 a French army of 48,000 under Louis d'Aubusson de la Feuillade was besieging the Savoy capital Turin, while another army of 44,000 under Louis Joseph de Bourbon, duc de Vendôme barred the Austrians' path from Lake Garda.
In fact, a Hessian army under the Crown-Prince of Hessen-Kassel, the future King Frederick I of Sweden, crossed the Alps and besieged Castiglione.