Pope Leo XIV had his inaugural mass on Sunday at Peter’s Square onboard a popemobile, to the delight of the estimated 150,000 pilgrims who had gathered there.

The mass, which marks the official start of the papacy of the Chicago-born cardinal Robert Prevost, is the biggest event to take place at the Vatican since the funeral of his predecessor, Pope Francis, in April. Leo is the first U.S. pope in the history of the Roman Catholic church.

Pope Leo XIV said he wanted the Catholic church to be a “small leaven of unity” in a time of “too much discord and too many wounds”, during his inaugural papal mass attended by world leaders including the Ukrainian president, Volodymyr Zelenskyy, and the US vice-president, JD Vance.

Calling for more love and unity, Leo said the church’s “true authority” was the charity of Christ. 

He said: “It is never a question of capturing others by force, by religious propaganda or by means of power. Instead, it is always and only a question of loving as Jesus did.”

The pope met Zelenskyy after the mass. In a message on Telegram, the Ukrainian leader said Kyiv was ready for talks in any format in order to get results for ending the Russian invasion of his country, adding that he was grateful to the Vatican for its readiness to host direct talks between Ukraine and Russia and “for its clear voice to defend just and lasting peace”.

Zelenskyy and Vance also discussed an upcoming phone call betweenDonald Trump and the Russian president, Vladimir Putin