It can also be the Spanish form of Joan. My grandparents lived in Puerto Rico for two years and the natives called my granny (whose name is Joan) Juana.
-- Anonymous User 11/3/2007
This name was also used by the Mexican writer Sor Juana Inés de la Cruz, a nun from 1600.
Queen Juana of Castile (1479-1555) was the daughter of Ferdinand of Aragon and Isabella of Castile and a sister of Katherine of Aragon. Known as "Juana la Loca" ("Jane the Mad"), her mental health was often strained by her unrequited love for her unfaithful husband, Philip I of Castile, and by the control of her male relatives over her. Juana may well have been bipolar rather than truly mad.