Published in two volumes in 1862 and 1867, it was an important history of Christianity in Ireland, because Cogan made use of three sources of information: * folklore and memories of people alive in Meath the 1850s and 1860s (covering the period from the Penal Laws to the Irish Potato Famine (1845-49)) which were recorded in great detail. * access to the Meath diocese's archives; when the Roman Catholic Bishop of Meath moved from his former seat in Navan to the new cathedral in Mullingar in the early twentieth century (the diocesan seminary, St. Finians, also moved from Navan to Mullingar) the diocesan archives were lost in the process. How the priceless records, many of them by Cogan in his research in the 1860s, were lost remains a mystery; * access to papers relating to the chu