Meghan Markle's great-great-great grandparents were wed on this day, 159 years ago in the Church of Ireland parish of Donnybrook, Dublin.

On her visit to Dublin with Prince Harry last year, the young Duchess of Sussex discovered she is descended from a young Belfast woman named Mary McCague, who married English soldier Thomas Bird.

According to the Irish Independent, the January 23, 186,0 entry for Bird, a private in the 22nd (Cheshire) Regiment - based at Beggar's Bush Barracks, and McCague, then residing at Merrion Strand, is complete with smudges where the registry may have been closed before the ink had time to dry.

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GAA President John Horan (L) and Britain's Prince Harry and wife Meghan, Duke and Duchess of Sussex visit Croke Park in Dublin on July 11, 2018 during their two day visit. Markle was presented with documents detailing her Irish ancestry. (Photo FRANK MCGRATH/AFP/Getty Images)

GAA President John Horan (L) and Britain's Prince Harry and wife Meghan, Duke and Duchess of Sussex visit Croke Park in Dublin on July 11, 2018 during their two day visit. Markle was presented with documents detailing her Irish ancestry. (Photo FRANK MCGRATH/AFP/Getty Images)

The discovery was made by Fiona Fitzsimons and Helen Moss of Eneclann, a genealogical research firm.

"It was known that Thomas Bird was in the army, but no one had thought to examine whether he might have served and married his Irish wife in Ireland. With this as our starting point we were able to follow Meghan Markle's family to Malta and then to New Brunswick, in Canada," they explained.

While the parish registry identifies Meghan's great-great-great grandmother as Mary McCue, she signed herself as Mary McCague. Thomas Bird signed the registry with an 'x' meaning he could not read or write.

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Within six months of their marriage, the 22nd Regiment, which Thomas belonged to, was sent to Malta in June 1860, and the couple left Ireland on board the steamship Olympus.

In 2016, Eneclann launched the Irish Family History Centre, based in CHQ Building and partnered with EPIC, which Prince Harry and Meghan visited during their trip to Ireland.

Britain's Meghan, Duchess of Sussex greets well-wishers after her visit with Britain's Prince Harry, Duke of Sussex to Trinity College in Dublin on the final day of their two day visit on July 11, 2018. GERRY MOONEY/AFP/Getty Images)

Britain's Meghan, Duchess of Sussex greets well-wishers after her visit with Britain's Prince Harry, Duke of Sussex to Trinity College in Dublin on the final day of their two day visit on July 11, 2018. GERRY MOONEY/AFP/Getty Images)

What do think of the royals Irish heritage? Let us know in the comment section.

Meghan Markle, the Duchess of Sussex, can trace her ancestry back to Mary McCue, a young Irish woman from Belfast who married Thomas Bird, an English soldier, at Donnybrook in 1860 .Getty Images