King Charles III vowed to uphold parliamentary democracy and follow the "selfless duty" of his mother, Queen Elizabeth II, in a key address at Westminster Hall that offered a glimpse of how he intends to carry out the role of monarch.
Receiving messages of condolence from the speakers of the House of Commons and the House of Lords, the king said he felt "the weight of history" surround him, and hailed Parliament as "the living and breathing instrument of our democracy."
In a clear indication that he would not further involve himself in democratic affairs, Charles praised the "vital Parliamentary traditions" that work "for the betterment of us all."
It was the second time in recent days that Charles had stressed the importance of Parliament's independence from outside interference, in a signal that as king he would refrain from sending the controversial "black spider letters" he had written -- while he was heir to the throne -- to the government, on issues ranging from the environment to the Iraq War.
"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," Charles said. "She set an example of selfless duty, which, with God's help and your counsels, I am resolved faithfully to follow."
During the ceremony, the king sat just meters from where his namesake, King Charles I, was tried and condemned in 1649 after the civil war with parliamentarians.
House of Commons Speaker Lindsay Hoyle also reminded the new king of the primacy of Parliament and his role as a constitutional monarch, saying: "We know you hold the greatest respect, the precious traditions, the freedoms and responsibilities of our unique history and our system of parliamentary government."
Charles was set to fly to Scotland on Monday to embark on a tour of the United Kingdom, which would see him lead a procession carrying the queen's coffin through Edinburgh. He was also scheduled to hold an audience with Scottish First Minister Nicola Sturgeon before attending a vigil alongside other members of the Royal Family and senior politicians including the prime minister, Liz Truss.
Today, the queen's coffin will be flown in a Royal Air Force aircraft from Edinburgh to London. On Wednesday afternoon, large crowds will witness a procession through the capital as she is carried from Buckingham Palace to the Palace of Westminster. Ceremonial viewing areas will be arranged along the route for the public to observe, and the event will be broadcast on a screen at Hyde Park.
The Queen will then lie in state in Westminster Hall for five days, from 5 p.m. Wednesday to 6.30 a.m. Monday, the day of her funeral. Members of the public will be able to file past 24 hours a day, and there are expected to be long lines and waits of 11 hours or more.
Her closed coffin will rest on a raised platform and will be draped in the Royal Standard with the Orb and Sceptre placed on top, the UK government said in a statement.
Prince Harry also released a tribute to the late queen Monday, describing her as a "guiding compass" to many.