Medieval sources from the 6th through the 15th centuries A.D. were reviewed in order to determine the probable age of menarche. Reported ages at menarche ranged from the 12th to the 15th years.
Amundsen, Darrel W. and Diers, Carol Jean
"The Age of Menarche in Medieval Europe,"
3, Article 6.
Available at: https://digitalcommons.wayne.edu/humbiol/vol45/iss3/6