Pope Francis declared a jubilee year on Friday, the second anniversary of his election.

The year will also celebrate the 50^th anniversary of groundbreaking reform in the Catholic Church, and was given the theme of mercy.

The year of jubilee will begin on December 8 — a date that Francis said is "of great significance, for it impels the Church to continue the work begun at Vatican II." December 8 is also the date of the Feast of the Immaculate Conception, and the date when the Second Vatican Council closed in 1965. The jubilee year will end on November 20, 2016.

The Vatican II most notably changed the language of Catholic services from Latin to common vernaculars, and instituted other changes that marked the Church's more modern perspective.

Debates on how the Church should best reach today's Catholics have increased under Francis' pontificate, with the pontiff's liberal approach to homosexuality, divorced Catholics, and other issues causing dissention between conservatives and liberals within the Church.

Increased discussion of these issues is expected to occur when Church leaders meet in Vatican City in October.

The declaration of a jubilee year coincided with Francis affirming that his tenure as pope may be shortlived.

"I have a feeling my pontificate will be brief," he told Mexico's Televisa on Friday. "Four or five years, I don't know. Two years have already gone by.

"It is a vague feeling I have that the Lord chose me for a short mission. I am always open to that possibility."

Francis made similar comments in May, when he expressed admiration for Pope Emeritus Benedict XVI, the first pontiff to resign since the year 1415.

"If and when the time comes," Francis said, "I will do what the Lord tells me to do, pray and try to find God's will. But I think that Benedict XVI wasn't a unique case."