In Italy, Archduke John battled Napoleon's stepson Eugène. The Austrians defended against several bungled French assaults at the Battle of Sacile in April, causing Eugène to fall back on Verona and the Adige River. Eugène was able to concentrate his forces while John detached troops to support Charles. John won victory at the 30 April Battle of Caldiero but was forced to retreat due to Eugène's increasing superiority and the movements on the Austria-Bavaria front. John was defeated in the 8 May Battle of Piave River and forced out of Italy. Eugène detached MacDonald to pursue John and joined Napoleon at Vienna with the rest of his army.