After conducting a thorough search, I was unable to find any concrete information on a person named Frate Leone Testo. However, I did find some possible leads:
The text of the blessing reads (in translation): frate leone testo
Frate Leone’s "write-up" of Francis was not intended to be a biography in the modern sense, but a spiritual preservation. He is often credited with assisting in the composition of the Canticle of the Sun and recording the Testament of St. Francis . After conducting a thorough search, I was unable