AIB and Citibank will square up to each other at trial in a New York court on January 25 in a $500m (€447m) showdown that's been over a decade in the making.
State-owned AIB is trying to win damages from the US financial giant in relation to its alleged role in the $691m (€617m) John Rusnak rogue trader scandal.
After years of protracted legal arguments, the judge hearing the case, Deborah Batts, has just set the trial date.
It's slated to last between two to three weeks and will dredge up what was a major international event back in 2002.
Allied Irish Banks launched the legal action in 2003 against Citibank and Bank of America after John Rusnak, who was a currency trader at AIB's then US subsidiary Allfirst, racked up massive losses that he had hid from the bank.
Citibank was Allfirst's prime broker. Bank of America settled AIB's case against it in 2012.
AIB has accused Citibank of furthering Mr Rusnak's fraud by engaging in his sham transactions, something Citibank denies.
Ms Batts said during the summer that there was "credible" evidence that Citibank misled AIB regarding Mr Rusnak's trades.
"Given how lucrative Rusnak's trading was to Citibank, it would not be far-fetched to infer that Citibank did so because it was motivated to keep Rusnak happy," she said.
But Citibank argued that it had "no duty to determine or judge the bona fides" of the transactions made by Mr Rusnak which it confirmed.
Citibank moved to have the case dismissed, but AIB countered that the defendant was merely relying on arguments that had it had previously made a number of years ago in court and which had been rejected at the time.
Ms Batts rejected all of Citibank's efforts to derail the case by seeking either a summary judgment or an interlocutory appeal. The decision of in an interlocutory appeal would not have been known until late 2016 or 2017, further delaying a trial, AIB had argued.
Citibank had also asked the judge to reconsider a June conclusion made by the court that a "reasonable factfinder could find that Citibank made material misrepresentations in the confirmations it sent to Allfirst".
But Ms Batts said that Citibank had relied on "artful quotes" from other cases it also used when it sought a summary judgment in the case.
"The arguments are no more persuasive now than they were then," she said.
AIB said the case has involved extensive paperwork, including 680,000 documents, hundreds of hours of recorded telephone calls, more than 100 fact depositions on three continents and 15 expert reports.
AIB sold Allfirst to US bank M&T in 2003.
Mr Rusnak pleaded guilty to bank fraud in 2002 and was sentenced to seven-and-a-half years in prison. He served six.