She was probably from a wealthy family, as shown by her ability to reference both theological works in Latin and courtly poetry in French. At some point in her life, she seems to have been the head of a beguine community for a while before leaving. At this point she took up a wandering life, unusual but not unheard of for a beguine.
* Though we don’t actually know for sure that she lived there.
** Some argue that she died in the 1260’s. Others think she was still writing poetry in 1300.
General:
Walter Simons, Cities of Ladies: Beguine Communities in the Medieval Low Countries, 1200-1565, 2001. (Note: To read bits of this book, try here.)
Hadewijch of Antwerp: The Love Mystic - Medieval Women Writers
Hadewijch - Wikipedia
Poetry:
Hadewijch of Brabant and the High Palace of Love - Amazing Grace
Poems in Stanzas by Hadewijch of Brabant - Medieval Christianity
Hadewijch - Poetry Chaikhana
Stanzaic Poems - Medieval Women Writers
Letters:
Hadewijch Letters - Medieval Women Writers
Hadewijch - Digitale Bibliotheek voor de Nederlanse letteren (Note: This site is all in Dutch. As a result, I've only puzzled out a bit of it, but it looks pretty useful if you speak the language.)