From the Marches, he has always been devoted to the Virgin of Loreto. He said "My parents used to go to the Holy House every year and take my brothers and me with us". Elected Pope on June 16, 1846, he took off his pectoral cross and ring and sent it to the Sanctuary of Loreto to which he donated on August 14, 1855 a copy with autograph signature of the proclamation bull of the dogma of the Immaculate Conception "Ineffabilis Deus"
On 26 August 1852 he wrote in the apostolic letter Inter Omnia “Among all the churches raised in the burden of the Immaculate Blessed Virgin and Mother of God, the Holy House of Loreto shines admirably. Precisely in that house the Blessed Virgin, by eternal divine disposition remained free from original sin, was conceived, given birth, nourished and greeted by the Angel full of graces, blessed among women and full of God "