The correspondence of Cardinal Paul Cullen and Archbishop Tobias Kirby is part of a digitisation project by the Pontifical Irish College in Rome. The collection of letters sheds light on Irish social and political history as well as ecclesiastical history. A highlight of the collection is a letter from Daniel O’Connell to Cullen in which he outlines sixteen reasons for the repeal of the Union as well as asking for the Pope’s blessing (Cullen Catalogue, 727 8 May 1842). Other letters cover local clergy, temperance campaigns, education and letters from places as varied as South Africa, Hong Kong and Canada. An outline of the collection, the project, and potted biographies of the clergy is given by archivist Vera Orschel in History Ireland.
Unfortunately there are no transcriptions of the correspondence only digitised images of the holograph letters. Navigation is a little awkward; you need to gather the information from the list of online catalogues and then search separately for the image.