Jacobus de Voragine
The oldest textual source of her "Life" seems to be the "Legenda Aurea" ("Golden Legend", also known as the "Historia Longobardica" or "Flos Sanctorum") of Italian chronicler Jacobus de Voragine, compiled around 1275 AD. This was an influential book on Renaissance spirituality and the understanding of sanctity which was read not only as a hagiography - a collection of lives of the saints - but as a "vade mecum", a manual of asceticism. This is the manner in which Ignatius of Loyola employed it and how Teresa of Ávila advised her spiritual sisters that it should be used.