At the beginning of the War of the Fifth Coalition, an army under Archduke John of Austria invaded Italy. Surprised by the early timing of the invasion, the French commander Eugène de Beauharnais left garrisons at Osoppo and Palmanova and fell back to Sacile. Eugène unwisely attacked John's army and was defeated in the Battle of Sacile on 16 April 1809. Subsequently, the French general retreated to Verona. Meanwhile, John left a brigade under Zach to blockade the fortress of Palmanova. After John's retreat from Italy and the Battle of Piave River on 8 May, Johann Kalnássy's brigade became separated from the main army. Zach joined Kalnássy and both fell back across the Isonzo River into Carniola (modern-day Slovenia) on 13 May 1809.