1) It's the oldest surviving book/manuscript in Ireland and the second oldest collection of the Psalms in the world. I dig history.
2) It was the first recorded case of copyright infringement in history (even more relevant in this digital age) and the resulting dispute led to the Battle of Cul Dremhe in 561.
How is 'An Cathach' Pronounced?
‘An Cathach’ is an Irish/Gaelic term which translates as ‘The Battler’. Pronounced An (On) Cathach (Kah-hah. The 'Kah' is pronounced with a hard C).
A Brief History:
It was said to protect, guarantee victory in war and was used as a talisman in battle. The original is still intact, as is the casket in which it was carried. The manuscript is in the Royal Irish Academy in Dublin, while the casket is in the National Museum of Ireland. It is traditionally associated with St. Columba (also known as Colmcille).
St. Columba borrowed the psalter of Saint Finnian under the pretense of reading it and began to copy it closely. Upon discovering this, Finnian demanded both the original and the copy back. Colmcille resisted and claimed that it was made from a miraculous light. Finnian was furious and brought the matter to the High King of Ireland, Diarmait Mac Cerbhaill.
The king examined the original psalter and its clone after which he proclaimed, "To every cow belongs her calf, therefore to every book belongs its copy.” The book and copy was returned to St. Finnian, much to Colmcille's annoyance. This led to the Battle of Cul Dremhe in 561 where supposedly thousands died and where Colmcille eventually reclaimed the book.
More information can be found at The Royal Irish Academy