The first men who really systematically explored the regions of ice and snow were Horace-Bénédict de Saussure (1740-1799), as regards the Pennine Alps, and the Benedictine monk of Disentis, Placidus a Spescha (1752-1833), (most of whose ascents were made before 1806), in the valleys at the sources of the Rhine. In the early 19th century the Meyer family of Aarau conquered in person the Jungfrau (1811) and by deputy the Finsteraarhorn (1812), besides opening several glacier passes, their energy being entirely confined to the Bernese Oberland. Their pioneer work was continued in that district, as well as others, by a number of Swiss, pre-eminent among whom were Gottlieb Samuel Studer (1804-1890) of Bern, and Edouard Desor (1811-1882) of Neuchâtel. The first-known English climber in the Alps was Colonel Mark Beaufoy (1764-1827), who in 1787 made an ascent (the fourth) of Mont Blanc, a mountain to which his fellow-countrymen long exclusively devoted themselves, with a few noteworthy exceptions, such as Principal J.D. Forbes (1809-1868), A. T. Malkin (1803-1888), John Ball (1818-1889), and Sir Alfred Wills (1828-1912).