The War of the Fifth Coalition was fought in the year 1809 by a coalition of the Austrian Empire and the United Kingdom against Napoleon's French Empire and Bavaria. Major engagements between France and Austria, the main participants, unfolded over much of Central Europe from April to July, with very high casualty rates for both sides. Britain, already involved on the European continent in the ongoing Peninsular War, sent another expedition, the Walcheren Campaign, to the Netherlands in order to relieve the Austrians, although this effort had little impact on the outcome of the conflict. After much campaigning in Bavaria and across the Danube valley, the war ended favourably for the French after the bloody struggle at Wagram in early July.