Newly elected Pope Francis offered a homily Tuesday during his installation mass in Rome.
Close to 200,000 people crammed into Saint Peter's Square to see it.
The pontiff rode in an open-air vehicle, stopping several times to reach out to pilgrims.
At one point, he even climbed out of his jeep and blessed a severely disabled man.
The new pontiff's first day as leader of the Catholic church worldwide was also marked here in San Antonio with a special mass held in Spanish.
Pope Francis is the first pope ever elected from Latin America.
Archbishop Gustavo Siller, the celebrant in a rare mass on the feast day of Saint Joseph, was also celebrating his 10-year anniversary as a bishop.
"I received a call that (then-Pope) John Paul II had appointed me bishop in Chicago," Siller said. "That was in January. The date the cardinal gave me was March 19."
Ten years later, he still celebrates this day -- now suddenly made even more important.
"Even the church chosen for this monumental day in Catholicism is special," Siller said. "Our Lady of Guadalupe Chapel is very small. And our pope's new motto: 'simple, but chosen.'"
The pope's homily at his installation called on Catholics to find a way to take care of the weak, poor and needy of the world.
"We needed a sign of hope, not necessarily from the Holy Father, but in this case, it's very fitting that the Holy Father is Latino," Siller said.
After the mass at the Mexican American Catholic College, the congregation was invited to a lunch to celebrate, complete with an anniversary cake.