Herman Didrich Janson (8 July 1757 â 13 March 1822) was a Norwegian shipper, businessman and powerful figure, and owner of DamsgÃÂ¥rd hovedgÃÂ¥rd, which he bought at auction in 1796. The gardens were often known as the Janson-gÃÂ¥rden and as the Jansonmarken. The property was in the family's ownership until 1983.
Herman Didrich Janson was also the owner of StiftsgÃÂ¥rden from 1805, an estate which he sold in 1809 to his stepson, County Governor Edvard Hagerup.