In medieval England Hilaria was used as a corruption of Eulalia.Here's what I've just added as a "user-submitted name" regarding the similar Elaria:An English medieval form of Eulalia. It was caused by a confusion of the second L with R in local speech, and this also resulted in Hilaria in medieval records, as distinct from the male name Hilary. The cult of St Eulalia spread from Spain and France to the English West Country, where, like Ellery (a corruption of Eulalie)for girls, this name, Elaria, seems to have been used the most. It has been used occasionally in England up until the present day, a search of genealogical sources suggests.
Here's what I've just added as a "user-submitted name" regarding the similar Elaria:
An English medieval form of Eulalia. It was caused by a confusion of the second L with R in local speech, and this also resulted in Hilaria in medieval records, as distinct from the male name Hilary. The cult of St Eulalia spread from Spain and France to the English West Country, where, like Ellery (a corruption of Eulalie)for girls, this name, Elaria, seems to have been used the most. It has been used occasionally in England up until the present day, a search of genealogical sources suggests.