Napoleon was enraged at his stepson's fumbling and he proposed to replace him with Marshal Joachim Murat who was King of Naples at the time. Nothing came of this threat because by the time his letter arrived, Eugène was advancing again. The viceroy had accumulated reinforcements as he retreated, so that his army numbered 60,000 by the time it reached the Adige. Meanwhile, John's army shrank as it detached a force to observe Venice and a brigade to reinforce Chasteler. News of Napoleon's victory over Archduke Charles at the Battle of Eckmühl on 22 April caused Archduke John to fall back toward Austria at the beginning of May. The next engagements between John and Eugène were the Battle of Caldiero in the last days of April and the Battle of Piave River on 8 May.