A DIGITAL record of the land transfer after the Cromwellian conquest of Ireland has gone live, detailing the 17th century landlords in every county and parish.
The Down Survey has been put online by researchers at Trinity College Dublin detailing the removal of Catholic landowners and the creation of country estates for Protestant merchants and soldiers.
It was the first time in the history of the world that a country had been so extensively mapped.
Dr Micheal O Siochru, associate professor in modern history in Trinity, said it is an extraordinary and unique resource allowing people to reconstruct the colonial land redistribution.
"We've never had the kind of technology to do this. For me as a 17th century historian it's jaw dropping," he said.
"Some of the maps are in magnificient condition, beautifully coloured and engraved. They are beautiful woks of art and it's the first time in 300 years that this collection has been back together."
The digital record opens up access to information on what Ireland's 32 counties, 240 baronries, 2,000-plus parishes and 62,000 townlands would have looked like centuries ago and who took control of them.
"This was a colonial enterprise," Dr O Siochru said.
"They decided to start with a clean slate. Nothing had been done to this scale in Europe before.
"And the digital record now allows an extraordinarily-nuanced exploration of the 17th century. We can ask questions to which we never knew the answers."
The Down Survey referred to the method of putting down chains to measure the land to a one inch scale known as a perch, and record topographical features from churches to roads, rivers, bogs, woods and settlements.
It was carried out by surgeon-general of the English army William Petty between 1656 and 1658, recording the country and the transfer of lands to merchants, adventurers and soldiers who supported Cromwell's campaign against the Irish rebellion after 1641.
Some of the original maps were destroyed in a fire at the Four Courts in 1711 and much of the rest in a second fire at the same building in 1922.
To complete the project, Trinity researchers recovered contemporaneous copies of the maps from libraries, archives and collections in Dublin, London, Edinburgh, Paris and Rome.
They include one that was stolen by French pirates in 1707 as it was being shipped from Ireland to England and later stored in the Bibliotheque Nationale in Paris.
People can use the maps on downsurveytcd.ie and explore how their own parish was transferred into new ownership. The originals have been overlaid on to Google maps allowing modern comparisons with the 17th century lands.
nformation mapping murders and violent assaults reported during the 1641 rebellion will also be included on the site along with an idea of what the road network looked like at the time and a database of over 10,000 landowners.