VATICAN CITY -- Pope Francis is celebrating the 65th anniversary of the ordination of his predecessor, Emeritus Pope Benedict XVI, with an unprecedented ceremony inside the Vatican featuring a reigning pope honouring a retired one.

Francis entered the Clementine Hall to applause Tuesday and went straight to embrace Benedict, who stood up and removed his white skullcap in a sign of deference.

Benedict then listened intently as Francis addressed him -- as "Your Holiness" -- lauding his 65 years of service to the church and saying his decision to retire to a small monastery was a very "Franciscan" thing to do.

Francis has recently dismissed new questions about the implications of Benedict's resignation by insisting that there is only one pope -- himself -- and that Benedict had pledged his obedience to him.