In short, their scheme went like this: They would deposit money in one another's banks but label those deposits as having been made by customers. Because customer deposits are viewed as more secure than those made by other banks, this was a way to defraud investors and creditors.
In doing so, they essentially inflated Anglo Irish Bank's deposit levels by about $8 billion.
That inflation was meant to obfuscate the funding crisis at Anglo Irish, which had invested heavily in a property bubble in Ireland that popped almost as soon as the financial crisis began in the United States.
As the crisis spread from the United States to the European Union, of which Ireland is a part, Irish banks were frantically asked to pay back loans and debts to American banks, but they couldn't. That, in turn, led to Ireland asking the EU for the most expensive bailout in its history.
"By means that could be termed dishonest, deceitful and corrupt they manufactured 7.2 billion euros in deposits by obvious sham transactions," Judge Martin Nolan said in his ruling. "The public is entitled to rely on the probity of blue chip firms. If we can't rely on the probity of these banks we lose all hope or trust in institutions."
Former Irish Life and Permanent chief executive Denis Casey was sentenced to 33 months. Willie McAteer, former finance director at the now-defunct Anglo Irish Bank, got 42 months. And John Bowe, Anglo Irish's former head of capital markets, got two years. The 74-day trial was Ireland's longest to date. The convicted have 28 days to appeal.
Nolan was unsparing in his critique of the men's business practices and called Anglo Irish "probably the most reviled institution in the state".
The public is entitled to rely on the probity of blue chip firms. If we can't rely on the probity of these banks we lose all hope or trust in institutions.
After he read their sentences, the former bankers were led away from the court to be transported to Mountjoy Prison, Ireland's largest.
Anglo Irish's two most senior executives, former chairman Sean FitzPatrick and chief executive David Drumm, are free on bail pending trials, which might not take place until next year. They face dozens of charges of fraud and concealment. Drumm fled to the United States in 2009, where he failed to win bankruptcy protection.
A US judge ruled that Drumm used his wife to shelter assets, and he subsequently spent five months in a US jail before being extradited to Ireland in March.
Ireland's Finance Ministry forecast last month that banks there might need 15 more years to fully recover from the hit they took after 2008.
No senior banking executives in the United Kingdom or the United States have been sent to prison over their roles in the financial crisis.