Exhibits at the Irish Military War Museum near Collon, Co Meath, explain the "complex political background" to the involvement of Irish men in two World Wars, guests at facility's official opening have heard.
Located on a 5,000sq ft site at Starinagh, the museum was established by William Sullivan and opened to the public last June.
It received funding from the Leader programme supporting development and enterprise in rural areas.
Minister of State for Defence Paul Kehoe performed the official opening on Friday ahead of this weekend's Living History festival at the site.
Displays include detailed reconstructions of first World War trenches, and exhibits which demonstrate the “highly motorised” conflict of the second World War.
The museum says it has “one of the finest collections of second World War Allied and Axis vehicles and deactivated weapons ever assembled in Ireland”.
Exhibits aim to explain "the complex political background behind why 210,000 Irishmen from both traditions fought in the mud-sodden trenches of France, Flanders and the Dardanelles during the first World War as rebellion tensions erupted back in Ireland".
Referring to Mr Sullivan, the museum's historian, Neil Richardson, said: "This is literally one man's collection. There's nothing like it anywhere on the island of Ireland, and you would be hard-pushed to find anything like it in Europe. Most of these museums are State-owned. This is a personal collection."
War memorabilia
Mr Sullivan said his interest in military history and memorabilia began when he was about seven or eight years old and he found a small coin from his grandfather, who was a sergeant in the Royal Irish Fusiliers.
He has travelled all over the world to assemble the collection just a third of which is on display: “I always had an interest in collecting. It didn’t matter what country or what period.”
Mr Sullivan said the collection was displayed in a way that followed the school history curriculum. He will shortly curate a 1916 collection to mark the centenary next year.
Visitors can handle original weapons and equipment, wear replica uniforms - and they can also pay to learn how to drive a tank.
The official opening was attended by current and former Defence Forces personnel and members of An Garda Síochána.
Mr Kehoe said it was a great addition to the list of attractions in the east of the country for Irish and overseas visitors.
“The time is now right to discuss these topics and consider in detail the sometimes controversial topic of Irish military history,” he said.