Here Fine Gael has accused the Department of Education of endorsing a garbled version of the country's history because it pays a fee of €450,000 a year for 4,000 Irish schools to access the Encyclopedia online.
Said Senator Fidelma Healy Eames: "This screwy version of events is a gross insult to our people and to our history. That it is being used to educate our children is even more ridiculous."
She likened it to saying that the first President of Ireland "was indeed Britney Spears, the Home Rule movement was led by Homer Simpson and the talks in Northern Ireland are currently being held by John and Edward -- such is the daft representation of these facts".
Encyclopedia Britannica Inc has apologised for mangling the history of the Irish Civil War by giving wrong dates, saying it took place in 1919-21 instead of 1922-23.
It also described the war as a fight between Catholic south and Protestant north, when in fact it took place entirely in the south between the Irish army and Irish rebels.
It even reports that Michael Collins, still mourned by many as Ireland's "lost leader", was killed in an ambush in November 1922 when the event took place in August of that year.
The Chicago-based publisher has launched an investigation after hearing of the complaints and insists that the errors exist only on older versions of its concise editions, which survive today mainly on handheld electronic devices.
It says Irish schools have access to the corrected version.
"We're obviously sorry that we ever got this information wrong in any edition ever," said company spokesman Tom Panelas. "I want to reassure Ireland that what its schools will be getting will not contain that information."
Senator Healy Eames said it was "beyond comprehension" that teaching material would document one of Ireland's most critical periods in history in such an inaccurate way.
"The Minister must ensure that this, and any other, inaccuracy in our schools' teaching material is sorted out right away."
The Department of Education agreed this year to begin providing the Britannica's online version to all 4,000 schools in the state, at a cost of €450,000 for annual access.
A Department spokesman says the matter is being referred to the National Centre for Technology in Education to review any inaccuracies.