On January 17, 1377, Pope Gregory XI moved the papacy back to Rome, from Avignon, where it had been since 1309. The Avignon Papacy spanned seven popes, from the French (Aquitanian) Clement V to Gregory. The decision to exit Avignon is credited partly to the efforts of Saint Catherine of Siena. In 1376, Catherine visited Gregory, serving as ambassador of Florence in an attempt to secure peace between Florence and the Papal States. Her diplomacy failed to quell the strife, but Gregory was apparently impressed enough by Catherine that he was persuaded to return to Rome.
Saint Catherine is referenced in Scott's "The Abbot", along with a footnote on her role in influencing Gregory's mind.
'..."They call me Lady Abbess, or Mother at the least, who address me,"said Dame Bridget, drawing herself up, as if offended at her friend's authoritative manner--"the Lady of Heathergill forgets that she speaks to the Abbess of Saint Catherine."...'