Catholic Encyclopedia
St. Mechtilde, born Matilda von Hackeborn-Wippra, blood sister of the Abbess Gertrude von Hackeborn, monastic herself. Quite plausibly the model for Matelda in Dante's "Purgatorio". She died in 1298.
Catholic Information Network
Essay on SS. Gertrude the Great and Mechtilde.
For All the Saints
St. Mechtilde is celebrated the same day (16 November) as her protégée St. Gertrude the Great.
The Ecole Glossary
Brief biography of St. Mechtilde of Hackeborn.