Mark Zuckerberg and Priscilla Chan paid more than €51m for Strancally Castle, the Gothic-style mansion and 178-hectare (440-acre) estate they purchased in Knockanore, Co Waterford.
The Property Price Register shows the Meta founder and his wife paid €51.17m for the property, far exceeding the estimated price of €20m to €30m when the sale was reported in August.
The purchase has been confirmed as one of the most expensive of all time for a residential property in Ireland, but the price looks restrained compared to some of these other Irish properties.
1. Walford, Dublin 4 - €58m
At the height of the Celtic Tiger in 2005, three nearby properties in exclusive south Dublin neighbourhoods sold for eye-watering sums, highlighted by the €58m paid for Walford.
The 4,000 sq ft Edwardian red-brick house on Shrewsbury Road had been advertised with a guide price of €35m and set a record for the world's most expensive house on a square footage when it sold at auction.
The 0,73-hectare (1.8-acre) property was purchased in a trust for Gayle Killilea, wife of disgraced property developer Sean Dunne. Dunne later denied that he had any interest in Walford during High Court bankruptcy proceedings.
The house was stripped of its 18th-century marble fireplaces while sitting vacant before selling for €15m -- a loss of €43m -- in 2011.
2. Strancally Castle, Co Waterford - €51.17m
Zuckerberg, who has an estimated net worth of $248.7bn, has given the Irish luxury property market a jolt by making Strancally Castle the most expensive home in Irish history.
The castle on the banks of the River Blackwater was built for former Conservative MP John Kelly in 1830 by the architects James and George Richard Pain. Previous owners Michael Alen Buckley and his wife Giancarla carried out extensive restoration works on the property, which extends to 16,000 sq ft.
Following the sale, a spokesperson for Zuckerberg said: "Mark and his family are excited to continue caring for this historic home and look forward to spending time in Ireland, where Meta maintains its international headquarters."
3. Belmont, Dublin 4 - €30m
Also sitting on tree-lined Shrewsbury Road opposite to Walford, Belmont sold for a reported €30m in 2005.
The Tudor-style house was built in the early 20th century and stands on two-thirds of an acre.
Formerly owned by businessman Tony Kilduff and purchased by an Irish family, the seven-bedroom property was extended to include an indoor swimming pool and sauna.
4. Dartry House, Dublin 6 - €30m
Completing the triumvirate of eight-figure Dublin house sales in 2005 in Dartry House, the former home of Irish Independent founder William Martin Murphy.
The protected structure had a south-facing turret added in 1900, and by the time of its sale by the Mill Hill Missionaries, it was mainly being used as office space.
Set on 3.9 acres beside the River Dodder, the main house, stables and outbuildings of Dartry House have since been converted into luxury guest apartments by developer Eugene Renehen.
5. Ballynatray House, Co Waterford - €29.25m
Further down the River Blackwater, Billionaire vacuum inventor James Dyson purchased Ballynatray House on the Cork-Waterford border for €29.25m two years ago.
Since then, the Brexit advocate has secured planning permission for a helicopter landing area on the 344-hectare (850-acre) estate, which will host performances as part of the upcoming Blackwater Valley Opera Festival.
He has also sought to carry out roof alterations, rebuild a stone chimney and remove an external staircase at the house, which is a protected structure with 350 windows.
Dyson, whose net worth is close to $20bn, acquired the property from Henry Gwyn-Jones, who previously purchased the estate for €11m.
6. Castlemartin, Co Kildare - €28m
John Malone, the billionaire behind Liberty Global, bought the Castlemartin for a reported €28m in 2014.
The 304-hectare (750-acre) estate features a stud farm, cattle breeding operations, as well as a restored medieval church and originally formed part of the vast Mount Juliet estate, established by the McCalmount family in 1914.
The property was formerly owned by Irish industrialist and publisher Anthony O'Reilly, who described it as his spiritual home.
7. Lyons Demense, Co Kildare - €25m
One of the grandest estates in Ireland, Lyons Demense was sold to a US businessman for about €25m in 2014.
The estate dates back to at least the 17th century and formerly belonged to Ryanair founder Tony Ryan, who spent £80m on renovations.
It was valued at €60m in 2009 before its eventual sale five years later. In addition to its renowned gardens, the property features a stocked lake, stud farm, gallops, stables and five additional lodges.
7. Luggala Estate, Co Wicklow - €25m
Luggala, the Co Wicklow estate built for the founders of Bank of Ireland and later owned by Guinness heir Garech Browne, sold for an estimated €25m in 2019.
When it was put on the market by the Guinness family trust in 2017, there were calls for the state to buy all or part of the 5,000-acre estate, which is adjacent to Wicklow National Park.
Under Browne's ownership, it served as a location for the television series "The Tudors," and Michael Jackson stayed there for several weeks in 2006.
The buyer has not been disclosed, but they are reported to be a private individual based overseas.
9. Auburn House, Co Dublin - €20.7m
Auburn House, a Malahide mansion on 11 hectares (27 acres), was sold by Mary McEvaddy to British developer Hollybrook for a reported €20.7m in 2019.
At the time, the sale was the most expensive in north Dublin since the property market crash and came after Hollybrook several adjoining sites.
The house dates back to 1779 and was restored by McEvaddy and her ex-husband, aviation tycoon Ulick, at great expense after purchase in 1996.
10. Castletown Cox, Co Kilkenny - €20m
The 208-hectare (513-acre) Castletown Cox estate in Co Kilkenny sold to an international buyer for at least €20m in 2018, more than the asking price of €17.5m.
Castletown was erected in 1767 for the Protestant Archbishop of Cashel, Michael Cox, and was modelled on Buckingham Palace.
The main building has 10 bedrooms with en suite bathrooms across two floors as well as a billiards room, ballroom, a gym, a vestuary and staff accommodation.
11. Abbey Leix Estate, Co Laois - €20m
Stripe co-founder John Collison (net worth €15bn) paid a reported €20m for the Abbey Leix estate in 2021.
The 2,500-square-foot 18th-century manor house sits on 453 hectares (1,120 acres) with 10 estate houses and cottages.
The house was designed in 1773 by architect James Wyatt and served as the home of the de Vesci for three centuries before it was acquired Welsh businessman David Davies in 1995.
Davies completed significant restoration and refurbishment works, and Collison has since commenced his own maintenance and refurbishment works.
*This article was originally published on BusinessPlus.ie.