The castle school, originally opened in 1722 and owned by the Danes, was handed over to the Basel Mission after the Danish colonial administration sold its assets on the Gold Coast to British authorities in 1850. Danish was the original medium of instruction at the Christiansborg School before a switch to the English language after the Basel Mission took over the operations of the school. A similar school existed at the Cape Coast Castle that primarily served mulatto children of Euro-African families on the coast. Regina Hesse was a polyglot - fluent in the Ga language, English, Danish and German. In 1850, when Regina Hesse was about eighteen years old, she was confirmed in the Basel Mission Church, Christiansborg and promoted from monitor to teacher. The following year in 1851, she moved into the household of her protégée, Catherine Mulgrave and her husband, Johannes Zimmermann. She later became the de facto headmistress of Catherine Mulgrave's girls' school at Osu. Additionally, Hesse had a great working relationship with her Mulgrave’s official successor, Rosina Stanger. Thus, Regina Hesse was influential in shaping the framework for the girls’ education programme through her efficient management and administration of the school. After her marriage in 1857, she became a full time missionary wife. She was also active in the women's Christian ministry and fellowship which led to a significant increase in congregants, including her own extended family, in her home church, the Basel Mission Church, Christiansborg, now known as the Ebenezer Presbyterian Church, Osu. Under her tutelage in the 1880s, more women participated in activities relating to Bible study and prayer meetings. In 1857, Regina Hesse married German native, Hermann Ludwig Rottmann, the first Basel missionary-trader in Christiansborg and the founder of the "Basel Mission Trading Company," first entered in the Commercial Register of Basel in 1859, under its German name, ""Missions-Handlungs-Gesellschaft Basel"". Rottmann's father was a German tobacco manufacturer. Rottmann had earlier completed his education in commerce in Hamburg, Germany's ""Gate to the Seven Seas."" After arriving on the Gold Coast in 1854, he opened a hardware shop in Christiansborg, selling goods and building materials for the local burgeoning construction industry: ropes, wires, hammers, saws, nails, bolts, hinges and door handles. This shop evolved into the Basel Mission Trading Company.