May's Florence speech was meant to jolt the divorce talks out of deadlock, three months after they began and to demonstrate some unity in her government - notably on remaining in the European Union single market and accepting its rules for a couple of years after Brexit, a bitter pill for some hardline opponents of European Union membership.
An agreement on orderly withdrawal was "a precondition for any constructive and trustworthy discussion on our future relationship with the United Kingdom".
Mrs. May's speech was also aimed at presenting the European Union with a coherent British position on Brexit after months of public disagreements between senior government officials.
MAY ON UK COURTS REFERRING TO EUROPEAN COURT OF JUSTICE "Over time. the rights of EU citizens in the UK, and UK citizens overseas will diverge".
However, the main opposition Labour Party accused May of expending more energy on disputes with her cabinet colleagues.
The Foreign Affairs Minister Simon Coveney said the speech provided "additional clarity" but warned there are "still many outstanding issues" and a lot of work to be done before negotiations can move on to Britain's future relationship with the EU.
Johnson will be in the audience when May makes her speech at the Santa Maria Novella church and museum, which some commentators dubbed an attempt at personal renaissance.
Mr Davis said that Britain would be paying "roughly" £10bn a year into the European Union budget during the two-year transition period.
The two-year "implementation period" was needed, May said, to "prepare and implement the new processes and new systems that will underpin that future [UK-EU] partnership".
May, as expected, ruled out Britain replicating relationships the EU has with other countries in its own post-Brexit relationship with the bloc, including the so-called "Norway model" where Britain would stay in the single market as a member of the European Economic Area (EEA).
A figure was not given, but this was taken as a clear hint that the Government would be willing to pay up to €20bn into the EU's budget during this period.
Some EU politicians gave May's landmark speech in Florence a cautious welcome, but British opposition leaders and political analysts said May had offered little new apart from the two-year transition.
May reiterated Britain's commitment to working with the European Union on defence and security, and defending stability with the bloc.
While the UK's Brexit Secretary, David Davis, said there was a "high degree of convergence" on that issue.
Poland's Europe minister Konrad Szymanski said there could be no transitional agreement without agreeing on the three key issues in the divorce talks. It is in our common interest.
The pound weakened about half-a-penny against the euro and three-quarters of a cent against the United States dollar during her speech, underlining the sensitivity of the talks to markets and firms, some of which fear Britain could crash out of the bloc without a deal.
The European Parliament, which will have a final vote on any Brexit deal when Britain leaves in March 2019, will vote a motion on the progress of the talks next month.
The idea is to break a deadlock in Brexit talks.
- Knicks agree to trade Carmelo Anthony to Thunder
- Week 4: The 5 Teams That Impressed Us The Most This Saturday
- After missile test, Donald Trump says Iran working with North Korea
- NFL New York Giants at Philadelphia Eagles: Preview and Prediction
- Notable stats from the Premier League weekend - Week 5
- McCain opposition may scuttle GOP health bill
- Pakistan Fans Overwhelmingly Choose Virat Kohli Over Their Own Batting Star
- Trio of Bills out against Broncos
- Tensions Continue to Rise Between the US and North Korea
- Oklahoma State down 2 offensive linemen against TCU