Baltazar Mathias Keilhau

Balthazar Mathias Keilhau (2 November 1797 – 1 January 1858) was a Norwegian geologist and mountain pioneer. He is regarded as the founder of the discipline of geology in Norway, and has also been credited for the discovery of the Jotunheimen mountain range.

Personal life Keilhau was born in Gjøvik to parish priest Johan David Bertram Keilhau and Johanne Marie Bodom. In 1830 he married Christine Kemp.

Keilhau made the first ascent of Falketind in 1820 along with two other climbers. He has later been labeled the "discoverer" of the mountain range of Jotunheimen. The mountain of Keilhaus topp is named after him. At Svalbard, the mountain of Keilhaufjellet and the glacier of Mathiasbreen are named after him.

He was appointed professor from 1834. Among his publications is the three-volume Gaea Norvegica (1838–1850). The first volume from 1838 describes the Oslo Geological Region, the second volume from 1844 covers Northern Norway, and the third volume from 1850 covers Southern Norway. This work is the first complete overview of the Geology of Norway.

He was decorated Knight of the Order of Vasa, Knight of the Order of the Polar Star, and Knight of the Order of St. Olav.