The story goes that Archbishop’s niece came to stay with him and promptly fell in love with a clergyman and eloped. The Archbishop was apparently heartbroken and a guilt-stricken niece put a letter of apology in one of his books in the library (why, oh why!). So, his ghost shows up to search the books for the missing note.
Below is a video about the library…worth a watch if you like Irish accents. Oh, and Irish history, of course! :)
If I ever have the opportunity to go back to Ireland, I will most certainly have a look at this beautiful…and haunted…library!