Hadewijch (sometimes referred to as Hadewych, Hadewig, ... of Antwerp, or ... of Brabant) was a 13th-century poet and mystic, probably living in the Duchy of Brabant. Most of her extant writings are in a Brabantian form of Middle Dutch. Her writings include visions, prose letters and poetry. Hadewijch was one of the most important direct influences on John of Ruysbroeck.
Read about Hadewijch in Wikipedia