EDINBURGH — The UK's new monarch King Charles III accompanied his late mother Queen Elizabeth II's coffin in a procession through the Scottish capital on Monday.

He walked behind his mother's coffin together with his siblings, Princess Anne, Prince Andrew and Prince Edward, as it was slowly transported from Holyroodhouse to St. Giles' Cathedral.

There, the crown of Scotland was placed on the casket draped in the Royal Standard of Scotland and adorned with the Queen's favorite flowers ahead of a service of prayer and reflection on the life and 70-year reign of the widely cherished monarch.

The Queen's coffin is to lie at the cathedral for 24 hours, giving members of the public a chance to file past and pay their respects.

On Tuesday, it will be flown to London, where the coffin will lie in state at the Houses of Parliament Palace from Wednesday afternoon until the morning of the funeral on Sept. 19.

Earlier, Charles addressed the UK's two houses of parliament in London.

Citing the “selfless” example of his late mother, Queen Elizabeth II — who died at Balmoral, Scotland, last Thursday, at the age of 96 — Charles pledged to follow her lead and uphold Britain’s “vital parliamentary traditions”.

He lauded parliament as the “living and breathing instrument of our democracy”, and nodded to Shakespeare’s Henry VIII by calling his predecessor a “pattern to all princes living”.

Charles, 73, has succeeded Elizabeth II as Britain’s monarch, with his wife, Camilla, 75, joining him as Queen Consort.

The couple sat on ceremonial chairs in Westminster Hall, with cavalry troopers in red tunics and plumed helmets standing to attention behind.

Charles said: "While very young, Her late Majesty pledged herself to serve her country and her people and to maintain the precious principles of constitutional government which lie at the heart of our nation. This vow she kept with unsurpassed devotion."

Among the country’s MPs and peers was newly appointed Conservative Prime Minister, Liz Truss.

The Lords Speaker, former Labour MP John McFall, and Commons Speaker Lindsay Hoyle, both offered their condolences.

The former commended Elizabeth as having been “a leader to, and a servant of, her people”, while the latter stated that people would lament “her loss ... around the world”.

At the end of the ceremony, the lawmakers present stood up to sing the national anthem, “God Save The King”.

Queen Elizabeth II was Britain’s longest-serving monarch, having ascended the throne 70 years ago.

Throughout her reign, she witnessed 15 prime ministers and some of the UK’s most important political moments, including the Falklands War, the Good Friday Agreement and the Brexit referendum. — Euronews