Nissens Pigeskole (Nissens Girls' School) was founded in 1849 by schoolmaster Hartvig Nissen. Today it bears the name of Hartvig Nissen Videregående Skole, and is open for both sexes. At that time, it was open for girls and young women only. In 1852 the girls might attend the school for 10 years, usually starting at the age of seven. In 1861 an almost two years' course was offered for older girls, preparing them for teaching in elementary school. In Norway admission to university studies for women started in 1882. Nissens Pigeskole was one of the first schools in the country starting to prepare women for university studies. The so-called "guvernante-klasser" prepared many Norwegian women for teaching at higher levels, and also for private teaching. For many years this was one of the few accepted occupations for female middle-class in the country.
Therese Bertheau never married, and she worked at Nissens Pigeskole all her life. Before that, she was a pupil at the school. She loved the school and was known as a strict but exceptionally good teacher. She was teaching English, French and German, and also translated many books to Norwegian.
The cache is a black plastic box.