VATICAN CITY (AP) — Pope Leo XIV took his first popemobile ride through St. Peter’s Square ahead of his installation on Sunday, waving from the back of the open-back truck to the crowd waving flags and cheering “Viva il Papa!”

It was a deliberate choice for Princess Charlene, Queen Letizia, Queen Mathilde and Grand Duchess Maria Teresa to wear white, and one that reflects their religion. The four royals are all Catholic and among an exclusive group of just seven women in the world who are allowed to wear white around the pope.

Fierce Nigerian political rivals Peter Obi and President Bola Tinubu were seen laughing and joking at Pope Leo XIV's inaugural mass in Rome. Tinubu of the All Progressives Congress defeated Obi of the Labour Party in the heated and tightly contested 2023 presidential election - a victory Obi challenged at the Supreme Court without success.

JD Vance is attending Pope Leo's inaugural mass. The trip could set the tone for the Trump administration's relationship with the new pope.

The service marks the official start of Leo's papacy just under a month after the death of his predecessor, Pope Francis. The ceremony began with a procession from St. Peter's Basilica — where Leo and other church leaders visited St. Peter's tomb to pray — to St. Peter's Square, where the Inauguration Mass was held.