Dublin: Encyclopaedia Britannica Inc. has apologized for mangling the history of the Irish Civil War in past editions, but stressed that Ireland's 4,000 schools have access to the corrected version.

Irish radio stations received irate calls this week complaining that the Britannica Concise Encyclopaedia describes Ireland's civil war as a 1919-21 fight between the Catholic south and Protestant north.

The war in reality actually happened in 1922-23, took place entirely within the south, and was fought between the Irish army and Irish rebels.

The Chicago-based publisher launched an investigation Tuesday after hearing of the complaints. It determined a day later that the Irish errors exist only on older versions of its concise edition, and survive today chiefly on handheld electronic devices.