A series of wars in Europe following the French Revolution. In 1791 Louis XVI attempted unsuccessfully to escape from France to Germany, to win support from Austria and Prussia. In April 1792 France declared war on Austria, which then ruled Belgium (the Austrian Netherlands). A series of French defeats followed until, on 20 September, an invading Prussian army was defeated at Valmy. In February 1793 war was declared against Britain, Spain, and the United Provinces of the Netherlands. For a year a Reign of Terror operated in France, but, at the same time, under the skill of Carnot, armies had been steadily raised and trained. At first the aim was to consolidate the frontiers of France along the ‘natural frontiers’ of the Rhine and the Alps, but from 1795, these armies were to conquer Europe. A number of brilliant young officers emerged, for example Bernadotte (later Charles XIV of Sweden), Barthélemy Joubert (killed in battle 1799), and above all Napoleon. All the Netherlands were conquered, Belgium being annexed, and the Republic of Batavia created from the United Provinces; French armies advanced across the Rhine and into South Germany. Switzerland was made into the Helvetic Republic (1798). In 1796–97 Napoleon took an army into Italy, defeated the Austrians at Arcola and occupied Venice, creating the Cisalpine and Ligurian Republics. In 1798 he led an expedition to Egypt, but the British fleet under Nelson destroyed his fleet at Aboukir Bay, and Napoleon returned to Paris. Meanwhile Austrian and Russian troops had re-occupied Italy and in 1799 Napoleon again marched across the Alps to defeat the Austrians at Marengo. At the same time General Moreau won a second great victory at Hohenlinden. The peace treaties of Lunéville (1801 with Austria) and Amiens (1802 with Britain) were then negotiated, ending the Revolutionary Wars.