Mozart and smallpox the imperial family were successful, and led to greater public acceptance for the procedure. Smallpox struck the Mozart family again in the next generation: Nannerl's eldest son Leopold and two of her stepchildren caught the disease during an outbreak in the Salzburg area in 1787. All three children survived. In 1796, the discovery of vaccination—the use of the related cowpox virus to immunize against smallpox—by Edward Jenner revolutionized the ability of medicine to deal with smallpox. Vaccination reached Vienna around 1800, when yet another local epidemic created impetus for its adoption. One of the doctors trained in the Vienna campaign,
Rhine Campaign of 1796 Germany. By the spring of 1796, Jourdan and Moreau each had 70,000 men while Bonaparte's army numbered 63,000, including reserves and garrisons. François Christophe de Kellermann also counted 20,000 troops in the Army of the Alps holding the area between Moreau and Bonaparte on the western side of modern Switzerland; there was a smaller army in southern France that played no role in the Rhine Campaign. According to plan, Kléber made the first move, advancing south from Düsseldorf against Württemberg's wing of the Army of the Lower Rhine. On 1 June 1796, a division of Kléber's troops led by François