The Catholic Church and the National Library of Ireland are working together to put thousands of parish records online. Almost 400,000 images of Catholic parish register microfilms are being made available to family researchers for free. A National Library of Ireland (NLI) statement called the records the single most important source of information on Irish family history prior to the 1901 census. Dating from the 1740s to the 1880s, they cover nearly 1,100 parishes throughout Ireland and consist primarily of baptismal and marriage records. “Most census records from this period were destroyed in the Four Courts fire of 1922, so these parish registers are the most comprehensive surviving source of information on Irish families in the 1700s and 1800s,” said Colette O'Flaherty, head of special collections at the National Library of Ireland. At the launch of the project in Dublin yesterday she said she believed that the digitisation "will be of huge assistance to those who wish to research their family history". "The NLI has worked with the Catholic Church to preserve these registers since the 1950s, when we were initially invited to make microfilm copies," she said. "Now, in the 21st century – and in keeping with our aim of enhancing accessibility through making our collections available online – we are delighted to embark on this major digitisation project." The information in the registers varies from parish to parish but typically includes the dates of the baptisms or marriages and the names of the key people involved, including godparents or witnesses. The microfilms have been available to visitors to the National Library of Ireland in Dublin since the 1970s. This new project means that, for the first time, anyone will be able to access these registers for free, on a dedicated website which will be launched next summer. Estimates put the number of people around the globe who claim Irish heritage at some 80 million, including more than 36 million Americans, 14 million Britons, 4.5 million Canadians, 7 million Australians and up to 1 million Argentines.