Calmus was used in Medieval Latin (
http://www.cognomiitaliani.org/cognomi/cognomi0003cali.htm); so the use of the feminine
Calma can be done as almost sure, since the presence of women (and thus feminine names) in Medieval documents is smaller that the presence of men.
But in the case of the Scandinavian royals, the use is the indicated by
Kate.
Lumia
http://onomastica.mailcatala.com