Greeted by a fanfare of trumpets and guarded by men in plumed helmets, Queen Elizabeth celebrated 60 years on the throne with an address to parliament in the medieval hall where one of her distant predecessors was sentenced to death.
The 85-year-old Queen addressed both the Lords and the Commons in Westminster Hall, an honour reserved only for monarchs and the most illustrious visitors. Since World War Two, Charles de Gaulle, Nelson Mandela, Pope Benedict and Barack Obama are the only non-royals to have enjoyed the privilege.
The hall is the oldest part of the sprawling riverside Palace of Westminster that houses parliament. Its magnificent hammer-beam roof, the largest medieval timber roof in Northern Europe, has survived fires and bombings that destroyed other parts of the palace many times over the centuries.
Since my accession, I have been a regular visitor to the Palace of Westminster and, at the last count, have had the pleasurable duty of treating with 12 prime ministers, said the Queen, 85, drawing laughter from an audience that included the latest three: Tony Blair, Gordon Brown and David Cameron.
In one of her previous addresses, for her Silver Jubilee in 1977, the Queen caused controversy by pointedly commenting on the benefits of union for all parts of her kingdom -- seen as a veiled warning against too much devolution of powers to Scotland, Wales and Northern Ireland.
With Scottish nationalism as lively as ever and a referendum on independence in the pipeline, the Queen chose to steer clear of politics for her Diamond Jubilee.
The happy relationship I have enjoyed with parliament has extended well beyond the more than three and a half thousand bills I have signed into law, said the Queen, who was wearing a pale yellow coat and matching hat.
Relations between monarchs and lawmakers were not always so smooth.
The throne where the Queen sat during Tuesday's ceremony was within inches of the spot where one of her predecessors, King Charles I, was tried for tyranny and treason and sentenced to death in 1649.
Since then, Britain's constitutional monarchy has weathered many storms before the palaces of Buckingham and Westminster settled into a cordial relationship.
Speakers of both houses, in traditional manner, heaped praised the queen's dedication to her subjects at Tuesday's ceremony.
The televised ceremony was precisely choreographed and involved officials with colourful uniforms and titles that have resisted the passage of time.
The Queen's Body Guard of the Yeomen of the Guard marched up the aisle of Westminster Hall with their Renaissance hats and ruffs while the Body Guard of the Honourable Corps of Gentlemen at Arms were also in attendance with their plumed helmets.
The Lord Speaker entered in procession with her Principal Doorkeeper as well as the Gentleman Usher of the Black Rod, while the Queen was escorted by the Lord Great Chamberlain.
She was greeted by a fanfare from the State Trumpeters of the Household Cavalry, perched on a balcony overlooking the hall, and presented with a newly made stained glass window showing her coat of arms, a gift from both houses.
(Writing by Estelle Shirbon)