EU leaders have vowed to set up a banking union during the course of 2013 after a Franco-German spat held up agreement on exactly when this vital crisis-fighting tool might come into force.
The decision took place in a calmer market environment on Thursday, but also against a backdrop of fresh violence in Greece, the origin of the three-year crisis, where a man died during a general strike and anti-austerity protests.
Following almost seven hours of talks, European Commission spokesman Olivier Bailly said there had been an 'agreement on a political framework for the end of 2012 and a gradual implementation in 2013'.
However, expectations the new body would begin its work from the start of the new year slipped amid discord between Europe's two powerhouses.
Diplomats said a final summit statement due after a second day of talks on Friday would commit the 27 EU states to 'agreeing' on a supervisor for eurozone banks by the end of the year.
But one European official said that even in the 'fastest scenario', it would be '(northern) summer 2013' before the supervisor saw the light of day.
And a French government source said that the European Central Bank would only be tasked with supervising all of the 6000 eurozone banks 'from the beginning of 2014'.
A German government source said the supervisor would have 'direct control of systemically relevant banks' and 'oversight of every bank in Europe in the case of risks arising', working with national regulators, which has posed problems for non-euro governments.
The basic idea is that in future, struggling banks in debt-racked countries that pose a danger to Europe's financial system could be recapitalised directly from EU bailout funds.
But this will not come in time for aid pre-agreed for lenders in Spain, which will have to add loans to its public debt burden.
A Spanish governmental source said Madrid had 'assumed' for the last month, since the German, Dutch and Finnish governments had rowed back on aspects of June's provisional agreement, 'that there wasn't going to be a direct recapitalisation' of its banks.
The Spanish official said the result of independent stress tests was that the recapitalisation would amount to 4.0 per cent of Spain's gross domestic product, 'which we can handle'.
The gathering in Brussels took place against a backdrop of calmer markets, but the crises in Spain and Greece continued to bubble away in the background and burst into violence in Athens.
Greek riot police fired tear gas at protesters on the sidelines of a large anti-austerity rally. A 65-year-old man collapsed and died from a heart attack but it was not immediately clear if his death was linked to the sporadic bursts of tear gas.
At the summit, Paris and Berlin clashed over the best way to end the three-year crisis, with France clamouring for rapid action on a banking union and Germany insisting there was no rush, during talks between German Chancellor Angela Merkel and French President Francois Hollande.
The leaders also appeared to differ over proposals from Berlin to beef up the power of the European Commission to supervise individual countries' budgets, handing the EU executive veto power if required.
Analysts said that markets had low expectations from this summit, but European stock markets closed higher for the fourth day as investors expressed greater confidence that the eurozone would eventually come to terms with the crisis.