Queen Elizabeth II last night paid her respects at the mausoleum of Sheikh Zayed, the founder and late President of the UAE, whom she considered a good friend.
Her previous invitation, in 1979, came from Sheikh Zayed himself, and the two had a close bond until his death in 2004, so it was fitting that his tomb was her first call on her official schedule.
Accompanied by Prince Andrew, the Queen's second son, who arrived earlier in the day, she and her husband Prince Philip, the Duke of Edinburgh, were driven to the tomb, which sits just outside the courtyard of the Sheikh Zayed Grand Mosque.
The royal party were guided into the mosque courtyard by Sheikh Mohammed bin Zayed, the Crown Prince of Abu Dhabi and Deputy Supreme Commander of the UAE Armed Forces.
Sheikh Mohammed was quoted on the state news agency WAM as saying the Queen and the Duke were "great guests" to the UAE.
The visit, he said, "launches a new stage on the path of strong relationships of cooperation and friendship that tie the two friendly nations and peoples".
Also joining them on the tour was Dr Ali bin Tamim, chairman of the Grand Mosque centre. It was the first time a head of state had visited the mosque since it opened for daily prayers in 2007.
After arriving from the northern side of the courtyard, the Queen spent much of her walk to the main entrance admiring the intricate marble tiles on the ground.
She was dressed in an ankle-length gold textured coat, with large gold leaf shaped buttons.
She modestly covered her head with a white hat, using a gold scarf to keep it in place and cover her hair. Prince Philip wore a blue suit with a white handkerchief in his top pocket.
After pausing briefly to allow media to photograph her, she removed her shoes and entered the mosque. Inside, she and Prince Philip were introduced to children aged between six and 14. All the children were reciting the Quran.
Inside was also the British foreign minister, William Hague, and his wife Ffion, who entered the mosque, which was surrounded by armed guards, shortly before the Queen's arrival. Mrs Hague was wearing a full abaya with a blue-coloured headscarf.
The British ambassador, Dominic Jermey, and the UAE Foreign Minister Sheikh Abdullah bin Zayed were also in the welcoming party at the airport. Speaking at a press briefing yesterday afternoon, Mr Jermey said the visit was important on a number of levels such as policy, defence and security. He also referred to next year's planned marriage between Prince William, the Queen's grandson, and Kate Middleton, saying he had been involved in a number of conversations about whether the couple might honeymoon in the UAE.
Today the Queen will unveil the much-anticipated design of the Zayed National Museum, due to open on Saadiyat Island in 2014.
The royal party will then be welcomed at Al Mushrif Palace, in the heart of the capital, for lunch with Sheikh Khalifa, President of the UAE and Ruler of Abu Dhabi, and other members of the Ruling family.
As part of the occasion there will be a 21-gun salute and a Guard of Honour, followed by a state banquet.
Yesterday, the main gates to the palace were flanked by poles carrying the Union Flag and the UAE's green, white and red flag.
Some of the main roads on the island were cleared yesterday afternoon, with marked police cars parked at junctions, to allow the official vehicles to pass through with ease.