[1][2] Born on 20 August 1895 in Askov, Vejen Municipality, in the south of Jutland, Margrethe Sofie Charlotte Appel was the daughter of Jacob Christian Lindberg Appel (1866–-1931), a folk high school headmaster and later a minister, and Ingeborg Schrøder (1868–1948), an early female gymnastics teacher.
Later, in 1919, while in Copenhagen she obtained professional teaching qualifications in Danish and in German, complemented by a study trip to Germany.
It must therefore have been difficult for her to accept her father's decision in 1928 to invite another couple, Karen and Jens Therkelsen Arnfred, to run the school following his retirement.
From 1934, she took a special interest in the girls who had been newly admitted to the school, instructing them in the responsibilities of women and encouraging them to appreciate music.
[1] After her husband died in 1951, Christiansen taught at Bordings Friskole and then at Snoghøj Højskole before heading a folk high school in Oldenburg for a period.