Former Republic of Ireland Under-19 manager Seán McCaffrey has died at the age of 58.
He was a founder member of Monaghan United, a club he also managed when he was just 23.
McCaffrey managed the Under-17 and 19 Irish teams, taking over from Brian Kerr, and was highly-regarded in the development of players.
He also had a spell in charge of Dundalk in 2012.
FAI chief executive John Delaney praised McCaffrey's contribution to Irish football: "It is very sad to learn of the passing of Sean McCaffrey, who was truly an inspirational character and someone who made a difference at all levels of the game.
"From his early days with Monaghan United to serving as an FAI Development Officer in the north east of the country and through to his masterful handling of the Republic of Ireland Under 19, Under 18 and Under 17 teams, he covered so much.
"While many people will rightly praise Sean for leading his Under 17 team in 2008 to the European Championships in Turkey, his real legacy lies with the numbers of players that he helped produce for the men's senior team, which was well into double figures and included the likes of Robbie Brady, Jeff Hendrick, James McCarthy, Darren Randolph and Aiden McGeady.
"Quite simply, Sean McCaffrey was a football man. He was passionate about the development of the game, he drove Irish football on, and he was always the same, whether he was dealing with a schoolboy starting out or one of the country's elite players.
"We send our deepest condolences to Sean's family and friends at this time and we will remember Sean's contribution to Irish football with a special presentation in the new year."
Dundalk FC added in a statement: "The club is saddened to learn of the death of former Dundalk FC manager, Seán McCaffrey.
"We offer our deepest condolences to Seán’s family and friends at this time. Ar dheis Dé go raibh a anam."