The letter is dated June 14th, 1773, and signed by St. Alphonsus de Liguori.
The translation is as follows:
June 14th, 1773
Long life to Jesus, Mary and Joseph. When I wrote to Msr. of Verali to thank him for the Just Don Foundation, I forgot to pray him to speak to the Pope about a new foundation to obtain his approval of his to give it more force to the work but please do not forget bringing him letter to pray him from my side for the new grace and please, if he didn’t already but maybe he did and if so, please thank him in my name. Please act in the way that you take in my name. Either or the other action with Msr di Verali. I wrote you another letter that you’ll probably receive with this. I recommend to you again what I wrote to you in that letter. I trust your prudence both don’t disappoint Mr. Arno and for the exact observance of the rules by all the Fathers and Brothers of this new house. I’m sending you by means of the Brothers Stephan and Anthony for the new house, one Umo Apostolico, one Dominic Halle and (untranslatable)
I’m sending you also another Domenic Halle. Please give it in my name to Dr. Arseneau. That is the Prior and Vice-Prior of Casa Maria, the man that held us so much in the foundation.
Please thank him for that from my side, from my heart. With blessings to you and everybody, many regards to Mr. Arno. The writer kisses your hand and salutes and embraces everyone in God. Msr. Alfonso ask me to open this letter after it was closed and the seal dried to add that please give everything you can to Mr. Arno. Please act in this way. He can’t complain for anything.
Brother Alphonsus Maria
On the other side of the letter, on March 4th, 1840, Giuseppe M. Mautone writes from Rome:
I, the Father Attorney of the Congregation of the Most Holy Redeemer and Postulator of the cause of canonization for St. Alphonsus Maria Ligouri, hereby declare that this letter was dictated by the saint and was signed by his own hand.
Pope Gregory XVI canonized him in May of 1839.