Pope's inauguration: From the Fisherman's Ring to who's going, here's all you need to know

Tens of thousands are expected to gather at St Peter's Square at the Vatican on Sunday for Pope Leo XIV's inauguration mass.

The service marks the official start of the new pontiff's papacy, and brings together royalty, world leaders and religious figures for yet another grand ceremony. But what happens during the service, and who is attending? What happens during the service? The service will start at 10am local time - 9am UK time.

The Pope tends to arrive at the basilica in the popemobile, waving to the crowd as he comes in. While it is a historic ceremony, each pope can make the odd alteration.

Pope Francis, for example, abandoned the bullet-proof popemobile frequently used by his more formal predecessor Benedict, instead opting for his open-top Jeep. He also wore a plain white papal cassock and black shoes in contrast to the luxurious red loafers that attracted attention under Benedict.

Midway through the journey to the front of the square, Francis got out to kiss a baby's head and shake the hand of disabled man in the crowd, before getting back in the converted vehicle. The Pope, in procession with the cardinals, enters the basilica.

Afterwards, he is presented with two major items that symbolise his new papal powers at the Vatican. One is the Fisherman's Ring, named in honour of the first pope, Saint Peter - who was a fisherman by trade.

It is a gold signet ring specially cast for each new pope, and typically bears the image of Saint Peter. The ring marks both the beginning and end of a papacy - when a pope dies, it is destroyed by the camerlengo, a senior cardinal.

He will also be presented with the pallium, a strip of lambswool which represents his role as a shepherd. It is placed on his shoulders before the mass begins.

Leo will deliver a homily to the public, laying out some of the themes of his papacy. Francis spoke of the need to serve one another with love and tenderness and not allow "hatred, envy and pride to defile our lives" and pledged to "open his arms to protect all of God's people and embrace with tender affection the whole of humanity, especially the poorest, the weakest, the least important".

Much of Leo's early rhetoric has centred around war, with his papacy beginning at a time when conflicts, including in the Middle East and Ukraine, rage on. Read more:Who is Pope Leo XIV? The Chicago-born baseball lover and first US pontiffPope Leo, keen tennis player, gets racket from world no 1 during Vatican meeting Overall, the service is expected to last around three hours, after which the Pope is expected to meet many of the attending world leaders.

Sky's Alastair Bruce and Siobhan Robbins will be at St Peter's Square to bring viewers the latest on Sunday. Who will be attending? Prince Edward, the Duke of Edinburgh, will represent King Charles at the inauguration, Buckingham Palace has said.

No reason was stated by the palace for the King's absence, but it is common for other royals to represent the monarch at St Peter's Square - Prince William did so for the King at Francis' funeral. Prince Edward will follow in the footsteps of the Duke of Gloucester, who represented Queen Elizabeth II at the inauguration of Francis in 2013, and his father, Prince Philip, who represented the Queen at Pope Benedict XVI's in April 2005.

Charles, then Prince of Wales, had represented his mother at the funeral of Pope John Paul II earlier that month. It is not yet clear whether Prime Minister Sir Keir Starmer, who went to Francis' funeral with his wife Victoria, will be at the Vatican again on Sunday.

Ukrainian president Volodymyr Zelenskyy plans to attend, according to his top aide Andriy Yermak, who said the leader would be willing to hold talks with other world leaders while he's at the Vatican, as he did with Donald Trump last month. Mr Yermak also revealed Leo told Mr Zelenskyy during a phone call on Monday that he was ready to facilitate such meetings and promised to "do his best" to help bring about a just and lasting peace.

There is no news from Donald Trump's camp yet on whether he will be at the inaugural mass of the first-ever American pontiff. JD Vance will return to the Vatican for the mass, according to his office, after visiting Italy last month and meeting Pope Francis the day before he died.

Before his appointment by the conclave, Leo had shared posts on social media that were critical of Mr Trump and his vice president, but the US president has so far only said Leo's papacy is a "great honour" for his country. Canadian prime minister Mark Carney has confirmed his attendance, with his office saying he would spend three days in Rome from Friday so that he could also "meet with other international leaders to discuss deepening trade, commerce, and cultural ties"..