A staggering collection of maps assembled in Trinity College Dublin (TCD) will reveal the exact ownership of the lands that were plundered from Irish families and given to landlords during the Cromwellian Plantation of 1670.
"We have never been able to do it to this level before – parish by parish, barony by barony, county by county," says TCD historian Professor Michael O Siochru of the 'Down Survey' map website, which will be unveiled tomorrow.
"If you are going to redistribute lands, then the first thing you have to do is map it and that is what happened," said Prof O Siochru, who is associate professor of Modern History at TCD.
"So the land survey – the first of its kind in the world – was carried out on Cromwell's orders.
"The results are amazingly accurate for the time."
The 'Down' refers to the chains that were literally "put down" on the ground to measure every inch of Ireland from the smallest parish to the biggest of the 32 counties.
The result was not only an incredibly detailed view of Ireland of the time but also provided a set of beautiful maps that have historic and artistic significance.
"It's such an exciting event," said Prof O Siochru. "Putting it all back together was like a detective mission."
The 1670 parish maps, which he described as "amazingly accurate", have now been digitised and loaded on to modern-day Google maps to give a complete picture of "who owned what".
With the aid of 'Books of Survey and Distribution' – "which categorised the huge transfer of land from Catholic families to the new Protestant ascendancy" – the result is that people all over Ireland will be able to research the ownership of lands in townlands going back to that time.
"From a historical point of view it is mind-boggling," said Prof O Siochru, who added that historians have been left amazed at the scope of the project.
"People will be able to look at their own parishes and see where people were living in the 17th Century – we have used it for two months in classes and it was a great hit with students – they all wanted to look up areas they came from or parts of the country they knew."
Putting the data together has also been something of a CSI-type operation after the original 'Down Survey' collection was destroyed in the first Custom House fire in 1711. However, copies made at the time and used 'in the field', survived. And more than 2,000 maps have now been traced to libraries and archives in Dublin, London, Edinburgh, Paris and Rome.
The reassembled collection will be unveiled at the launch of the Down Survey website in Trinity tomorrow.