Gemma Frisius

Gemma Frisius, born Jemme Reinerszoon in 1508, was a Dutch physician who also worked as a mathematician, cartographer, philosopher and instrument maker. He qualified as a doctor of medicine at the Old University of Leuven in 1536 and stayed on its medical faculty for the rest of his life, teaching mathematics, astronomy and geography alongside medicine. He made globes and mathematical instruments noted for their accuracy, including the terrestrial globe of 1536 and the celestial globe of 1537, and he described the method of triangulation for surveying in 1533. He died in Leuven in 1555, and he is counted among the founders of the Netherlandish school of cartography.