Johanne (Hanne) Ane Margrethe Nielsen (née Jacobsdatter, 11 September 1829 – 15 June 1903) was a Danish farmer who may have invented Havarti cheese. In the 1800s, Nielsen traveled around Europe to learn about cheesemaking. Her farm was named Havarthigaard and was close to Copenhagen. After returning from her travels, she developed the technique to create a new type of cheese. She was also a teacher, writer, and an accountant for the profit made from her butter and cheese. Her butter and cheese were served to royal families, including a cheese made with cumin that was served to King Christian IX of Denmark. She was denied membership of the Royal Danish Agricultural Society although she had sought the assistance of dairy scientist Thomas Segelcke. Despite being skeptical of female accountants, Segelcke included her accounting method in a book he published. Early life Nielsen was born on a farm in Søllerød near Copenhagen on 11 September 1829, close to the farm where she lived in 1902. She married Hans Nielsen when she was 19 years old and they lived in a home named Havarthigaard. Nielsen and her husband sold milk from their cows, but she was unhappy with the profit from the milk so she sold it as butter and cheese. Although Nielsen's attempts at selling butter and milk were successful from the beginning, she was not happy with the final products and decided to educate herself on better methods. Other farmers' wives were able to produce similar butter and cheese, but Nielsen wanted hers to be better than theirs. She studied subjects relating to dairy produce and traveled to Norway, Sweden, Switzerland and France, among others, to learn how to obtain better results. Nielsen learned how to make cheddar cheese with Joseph Harding in England, brie and Roquefort in France, and Gouda cheese along with Edam cheese in the Netherlands. Career Nielsen opened a dairy school on her farm where she taught a total of around 1,000 students from 1866 to 1903, many of them from Sweden. In September 1902, it was reported that all of the then-current dairy instructors in Denmark had received at least part of their training from her. She wrote press articles, held lectures, and published an 1886 Swedish manual on making butter. Nielsen won multiple prizes from the Royal Danish Agricultural Society, but the society did not allow her to become a member as they