So who are they and how will they hope to exert their influence?
Ursula von der Leyen
The new President of the European Commission hasn’t got off to the greatest of starts, only confirmed in her job by a narrow margin in the European Parliament, and then struggling to get her new team of Commissioners approved in the same chamber.
The rejection of the French Commissioner, in particular, led to a furious rebuke from President Macron. So she will take office from a position of weakness.
On the plus side, von der Leyen may escape the fate of Jean-Claude Juncker in having her time in office completely dominated by Brexit.
Assuming the UK leaves sometime early in 2020, she will have the chance to relaunch the EU of 27, and tackle some of the issues that have been on the back-burner since the Brexit crisis erupted.
That is the plan anyway.
But she will face a France that is becoming increasingly assertive, others who are getting pretty fed up with France throwing its weight around, and a Germany struggling to sort out its own leadership, let alone the leadership of the continent.
Much needs to be done.
Ursula von der Leyen will have a tough job showing she’s the one to do it.
Until recently the Prime Minister of Belgium, Charles Michel takes over from Donald Tusk as the President of the European Council - the key decision making body in Europe on which all 28 (soon to be 27) heads of state and Government sit.
The regular European summits in Brussels are meetings of this Council, and Michel will hold a key position in setting the agenda, guiding leaders towards a common position and speaking on behalf of them all.
Donald Tusk has been a firm friend of the UK, an outspoken critic of Brexit and major influence in ensuring that ‘no deal’ doesn’t happen by pushing for regular extension of the Article 50 deadline.
Charles Michel may be none of those things.
Much more closely aligned to France’s President Macron, Michel wants to get Brexit done.
If, by January 31, the UK has still not sorted itself out, there will be no one at the top of the Council pushing the others to remain patient.
Of course, the leaders speak their own minds and fight for their own national interests, but don’t underestimate the role that the President of the Council can play in pushing the collective decision making process in one direction or another.
Here’s a man who really needs no introduction.
The austere Frenchman with a penchant for reminding the British that “ze clock is ticking” is not fading into the background once Brexit is “done”.
In fact, he will be our daily reminder that Brexit is not done, that our departure from the EU merely marks the start of ‘Brexit 2 - Living Together Apart’.
Barnier has been appointed to lead the talks on the future relationship between the UK and the EU, in other words how we trade, whether we will charge each other tariffs, whether standards and regulations diverge, how much we continue to co-operate in areas such as Defence, Security, Policing, Space etc.
Backing him up will be his former deputy in the Brexit negotiation, Sabine Weyand, now the EU’s Director-General for Trade.
It’s déjà-vu all over again.
These talks could take years, and intimately tied up with them will be the issue of how long our transition arrangements will run.
The economic impact of both will be significant.
M. Barnier is going be a part of our lives for a while yet.
Once again, a former Prime Minister of Belgium, but one who has become much more familiar to us through his key Brexit role in the European Parliament.
Of course, we knew him long before Brexit as a regular sparring partner of Nigel Farage on the floor of the Parliament.
Today he is no less spiky, no less federalist in outlook, and - ironically - no less anglophile.
Brexit has genuinely distressed him, but ever since the referendum he has fought the EU’s corner tenaciously in the EP’s Brexit Steering Group.
The Parliament has a veto on the Withdrawal Agreement, and will have a veto on any future trade agreement as well.
However much many UK politicians may dismiss it, and in the process rubbish Guy Verhofstadt, neither can be ignored.