(1746–1805), Norway's richest person at the time. He and his wife Mathia inhabited his family's town house during winter, and used Frogner as their summer residence. They entertained extensively and invited the wealthy elite of Christiania to assemblés every week. In order to accommodate guests indoors on rainy days, they needed a large banquet hall. They fit it into an extension to the main building eastward, and to preserve symmetry they extended the building equally far westwards, to its present length of 54 metres. Among many foreign visitors Thomas Malthus enjoyed dancing in the ballroom in 1799 Bernt Anker died a childless widower in 1805. Frogner was bought by his nephew Morten Anker in 1807. His business was hard hit by the economic depression during and after the Napoleonic wars, and he eventually went bankrupt and was forced to sell Frogner by auction in 1836. The buyer was the director-general of the Modum Blue Colour Works, Benjamin Wegner, who was married to Henriette Seyler of the Hamburg Berenberg banking dynasty. They demolished the southern wing of the manor and opened the courtyard. The turret above the porte-cochère was dismantled and rebuilt on the roof of the main building during their time as owners. The Wegners, in their turn, went through economic problems during the financial crisis of 1848 and had to sell Frogner by auction. In 1848 Fredrik Georg Gade (1807–1859), a wealthy merchant from Bergen, purchased the manor. His heirs held the property in joint ownership, under the management of his son Gerhard Gade (1839–1909). He was married to an American, Hellen Allyne, and was the United States consul in Christiania. The former U.S. president and general Ulysses S. Grant visited Kristiania in the summer of 1878, and attended a gala dinner at Frogner with his entourage. Major parts of the farmland belonging to the manor was sold and built up through the end of the 19th century as the city expanded, but around one square kilometer remained when the city of Oslo bought the property in 1896 to secure space for further urban development and a new cemetery. The last private owner, Gerhard Gade, retained the right to inhabit the house until his death in 1909. This spared the house from demolition, and an economic recession prevented further building on the land. In the meantime, the house was recognised as an important cultural monument. It was restored and