Architecture and interior design thread

Yes, it's in Vitruvius:

Rules of thumb for determining satisfactory rise/run ratios have existed at least since Classical times. In De Architectura, Vitruvius suggests a unit rise of between 9 and 10 inches, and a unit run between 18 and 24 inches. To modern tastes, this proportion would create a very stately stair. Sir Henry Wooten (1568–1639) suggested that the unit rise not exceed 6 inches and that the unit run be between 1 and 1½ feet. Both authors, however, are describing public buildings or grand houses.

https://www.sizes.com/home/stairs.htm