The archivist and former chief custodian of the State papers, Breandán Mac Giolla Choille, has died. He was 86.
Mr Mac Giolla Choille died in New Jersey in the US last Saturday.
Born in Holywood, Co Down, in 1920, Mr Mac Giolla Choille worked in the State Paper Office until 1985.
His study 'Intelligence Notes, 1913-16, Preserved in the State Paper Office', assembled some of the most important documentary sources for historians of the Easter Rising.
It was published in 1966 by An Gúm as part of the events marking the fiftieth anniversary of the Rising.
After his retirement, the Public Record Office and the State Paper Office were amalgamated, and both functions were transferred to the National Archives.
Breandán Mac Giolla Choille was a founder-member of Foilseacháin Ábhar Spioradálta, a company dedicated to the publication of books on spiritual matters.
A former member of Bord na Leabhar Gaeilge, he was also active in other Irish language organisations.
He is survived by his wife Eilís, two sons (one of whom is RTÉ journalist Cathal Mac Coille) and three daughters.