The treasure trove of letters from Jackie Kennedy to Dublin priest Father Joseph Leonard lay undisturbed for more than 50 years in an old  safe at All Hallows College in Dublin, it has been revealed.

They were discovered by accident after two staff members at the former seminary invited a well-known expert in rare books to examine a rare medieval book they found at the college.

The valuer, Owen O’Neill, immediately informed the Sheppard’s auction house in County Laois when he saw the trove of letters from the former First Lady.

Among the revelations from Jackie are fears that her husband had a roving eye. She wrote: “I love being married much more than I did even in the beginning” – but expressed concern her husband would become like her father, who “loves the chase and is bored with the conquest — and once married needs proof he’s still attractive so flirts with other women and resents you.”

She also had a negative description of her mother-in-law, Rose Kennedy.

“I don’t think Jack’s mother is too bright – and she would rather say a rosary than read a book,” she wrote.

Jackie Kennedy became friendly with Father Leonard during a visit to Dublin in 1950 and maintained a correspondence with him for 14 years until his death in 1964.

At his funeral a huge bouquet of flowers was delivered on behalf of Jackie, still mourning the loss of her husband.

The letters offer a rare glimpse into the mind of Jackie, who zealously guarded her privacy.

The letters will be put up for auction on June 10th and it is expected they will go for close to $1.6 million dollars.

Jackie’s step-uncle W.S. Lewis first met Father Leonard in the 1920s and recommended that Jackie meet up with him during her visit to Dublin in the 1950.

Leonard met her and her step-brother Hugh Auchincloss at Dublin Airport and took them around Ireland, including a visit to the Blarney Stone

Auchincloss later stated “She loved the stories about the kings and castles in Ireland.

"She had a wonderful series of conversations with [Father Leonard] and then came back to America and got into a correspondence.”