### Instruction:
From the passage provided, extract when Susanna started as a principal.

### Input:
Susanna Gossweiler (1740–1793), was a Swiss educator. She was appointed the first principal of the girls' school Töchterschule in Zürich in 1774, and regarded a pioneer of women's education in Switzerland.

### Response:
Susanna started as a principal of Töchterschule in 1774.