While I was at Dr. Scott Hahn's Letter and Spirit Institute, I enjoyed many conversations with the Franciscan Friars of the Renewal (CFR) regarding Saint Francis and the Franciscan tradition. Especially helpful were Fr. Pio Maria Hoffmann and Br. Sebastian, not to mention Br. Paschal, Br. Felix, and Br. Simon.
I learned that first Life of Saint Francis was written by Thomas of Celano. Pope Gregory IX commissioned it and Thomas of Celano completed it by 1230. Remember, Saint Francis died in 1226 so that it is a contemporary account.
In 1247, Thomas of Celano produced a second version incorporating missing information.
I plan to read Celano's biography, especially since he retells how Saint Francis' stigmata were not mere holes in his flesh. Even more, something like nails grew into the wounds. I find this fascinating and hope to learn more about it. If anyone has anymore information about this detail, please share it with us.