Commentary Purg XIII 124-129

Before her death, Sapia's change of heart brought her back to the love of God and her neighbor.  As for Pier Pettinaio, whose second name is not a family name but an epithet denoting his profession, i.e., he sold combs to ladies (pettine means 'comb'), it was his prayerful intervention after her death that reduced her time in ante-purgatory.  Since she has been dead between twenty-five and eleven years, and since we would assume she would have spent at least a little time on the terrace of Pride, she has surely moved quickly up the mountain, sped by Pier's prayers.  For Pier see Pettinagno, Pier: A 'native of Campi in the Chianti district NE. of Siena, he was a hermit of the Franciscan Order, and dwelt in Siena, where he was renowned for his piety and miracles.  Ubertino da Casale ([Par XII 124]), in the prologue to his Arbor Vitae Crucifixae Jesu, mentions that he had received spiritual instruction from him.  Pier died on Dec. 5, 1289, and was buried at Siena, where he was long venerated as a saint, in a handsome tomb erected at the public expense.'