Pope Francis is now officially the head of the Catholic Church after his installation ceremony Tuesday morning in Vatican City where called on members of the faith to be "protectors of God’s plan inscribed in nature, protectors of one another and of the environment."
The pope began his day at St. Peter's Basilica, where he prayed at St. Peter's Tomb.
From there, the pope made his way to St. Peter's Square for the ceremony.
At one point he walked over to a group of disabled people and kissed the head of a man being held by an aide.
The crowd included leaders from more than 130 countries, along with representatives of other faiths.
It was a simpler installation than the one for Pope Benedict XVI in 2005.
Before the mass, Francis received his fisherman's ring which symbolizes his papacy.
The Vatican says he chose a simple, gold plated ring.
Unlike Pope Benedict, Pope Francis delivered his homily standing and without his miter. His message, delivered in Italian, was simple and direct.
"The vocation of protecting does not regard just us Christians. It has a dimension that precedes and that is simply human. It regards everyone. It is protecting the entire creation, the beauty of creation," Francis said.
Five hundred priests delivered communion to many of the faithful with military precision in about 15 minutes.
After the mass, the pope greeted world leaders who attended the service including Vice President Joe Biden, who led the American delegation.
Pope Francis, 76, is the first pope from Latin America.
His coat of arms will be the same one he used as Archbishop of Buenos Aires, but with the papal hat and keys added to symbolize his new role.
Francis will lead the world's 1.2 billion Roman Catholics, including more than two million in New York City.