Eugène commanded 70,000 Franco-Italian troops in his Army of Italy. Of his six French and three Italian infantry divisions, only two defended the Soča (Isonzo) River near the eastern frontier, while the rest were scattered across the Kingdom of Italy. On 16 April 1809, an overconfident Eugène gave battle with only one cavalry and five infantry divisions, about 35,000 infantry and 2,000 cavalry. At the Battle of Sacile, John's invading army mauled Eugène's army, inflicting 6,500 casualties for a loss of only 3,600. The defeated Army of Italy fell back to Verona on the Adige River gathering reinforcements until it had accumulated 60,000 soldiers. After John detached forces to besiege the Osoppo and Palmanova fortresses, and to watch the large French garrison of Venice, the Austrian army arrived before Verona with only 30,000 troops on 28 April. After hearing of the main Austrian army's defeat at the Battle of Eckmühl on 22 April, Emperor Francis I of Austria ordered his brother Archduke John to retreat to Inner Austria.