The visit marks the first time a British monarch will pray publicly with the Pope since the Reformation, symbolising unity between Anglicans and Catholics.
Upon their arrival, the royal couple were formally greeted by representatives from the Holy See at Ciampino 31st Wing Airport in Rome.
A significant event will be a joint prayer during an ecumenical service at the Sistine Chapel on Thursday, highlighting ongoing dialogue between the churches.
Buckingham Palace underscored the visit's historical importance and the necessity for Christian communities to unite in addressing global challenges.