The Second Austro-Sardinian war broke out in the summer of 1859. Leopold felt obliged to espouse Austria's cause. Victor Emmanuel II of Sardinia captured Tuscany in its entirety, and held it for the duration of the conflict; Leopold fled Tuscany as a result. The Peace of Villafranca allowed Leopold to return once more. Upon arrival, he abdicated in favour of his elder son, Ferdinand. Ferdinand IV's hypothetical reign didn't last long; the House of Habsburg-Lorraine was formally deposed by the National Assembly on 16 August 1859.