Whether it's the Brexit bill that comes first or the freedom of movement and protection of European Union citizens remains to be seen, but the main issue will be the fact that European Union negotiators want to leave trade talks at the end of the laundry list, whilst the British government and Theresa May in particular, had been looking for talks to be held in tandem. "A deal like no other in history", Davis said in a statement as he headed into the talks.
Here is everything you need to know and some of the key dates in the 15-month talks. That will involve everything from deciding what waters each side can fish in to how nuclear agreements should be renegotiated.
Theresa May had called for voters in the election to choose her "strong and stable leadership" to ensure that the United Kingdom had a strong hand in the Brexit negotiations.
Earlier, Boris Johnson said the talks would lead to a "happy resolution" for both sides.
But Mrs May confirmed the timetable remains on course and will begin next week.
EU Commission negotiator Michel Barnier.
The possibility of any trade deal is not expected to be up for discussion just yet.
Today's talks are expected to be the first of four or five sets of talks to be held over the summer concerning the first phase of the negotiations, namely the terms of Britain's departure from the EU.
THE Queen's Speech will be ditched next year to allow parliament more time to scrutinise new Brexit laws.
Included in the speech will be details on any legislation the Government requires to put Brexit into effect. Such an option would see Britain kept within the bloc's Single Market, a centrally-regulated trade zone in which migration is unlimited and effectively unvetted - leading to security risks and, in poorer member-states, brain drain.
PM Theresa May signing the letter to the European Union triggering Article 50.
Davis's agreement to Monday's agenda led some European Union officials to believe that May's government may at last be coming around to Brussels' view of how negotiations should be run for Britain's exit from the EU.
As has been the case throughout the run-up to the official talks, the main emphasis of the preview was on the U.K.'s desire to secure a future relationship with the EU.
Commons leader Andrea Leadsom said suspending next year's speech would help MPs and Lords build the "broadest possible consensus for our Brexit plans".
The EU hopes to finish withdrawal talks around October 2018. They should finally tell us what the aim is.
The UK General Election will have left Theresa May and Brexit negotiators floundering in the run up to today's initial meetings and how Britain will be looking to leave the European Union may have also fundamentally have changed, with the DUP having provided support to the Tories to remain in control by way of a minority government.
The Westminster vote will take place before the European Parliament debates and votes on the deal, effectively giving MEPs the final say on whether it will go ahead.
The EU says Britain can't leave without settling its bill, paying up for all its commitments that are still ongoing, including projects that might reach into the next decade, as well as the U.K.'s share of EU staff pensions.
Even though May triggered the two-year process on March 29, negotiators will have to get a full agreement much faster than March 2019.
Critics argue she is in a weak position to fight Britain's corner against European Union counterparts who question whether her writ still runs in Westminster. Every member state has incorporated the acquis into their legal system.
The EU has made its opening position clear.
Topics that will be discussed include trade and the cost of Britain's withdrawal.