Almost a couple of years ago, both Republic of Ireland and Northern Ireland qualified for a major tournament at the same time for the first time.
While Euro 2016 was memorable for two teams led by O'Neills, the North's bid to get to next summer's World Cup via the playoffs was halted controversially by Switzerland.
We'll hope Ireland have better luck against Denmark tonight!
With all that in mind, I was chatting to Northern Irish football journalist Michael Walker this week on Team 33 about his book Green Shoots: Irish Football Histories which tells the compelling tale of Irish soccer north and south via the stories of key men.
Beyond the individuals, the story of Belfast Celtic also caught my eye.
You can listen to the interview with Michael Walker on the podcast player or stream/download on iTunes:
Recent interviews on Team 33 include ex-England international Carlton Palmer, Chelsea legends Bobby Tambling and Paddy Mulligan, Dutch legend Johan Neeskens, ex-England striker Darius Vassell, Liverpool legend David Fairclough, former Ireland midfielder Mark Kinsella and former Everton forward Tomasz Radzinski. Plus our in-depth chats with Tony Coton, Packie Bonner, Nobby Solano, Ron Atkinson and Alan Curbishley are still available on iTunes. You can find them all in one place by subscribing to Team 33 on iTunes.
That club, of course, no longer exists, although it's story has not been lost in the near 70 years since their untimely demise.
Belfast Celtic's end at the culmination of the 1948-49 season was one topic Michael filled us in on and the nadir was St Stephen's Day 1948 in a match against Linfield which descended into anarchy because of members of the latter's fanbase.
"Belfast Celtic was formed on the Falls Road and came to be representative of the Irish, nationalist, Catholic population in the North. However, its recruitment policy wasn't based that way," Michael explains on the podcast.
"So Belfast Celtic crossed the divide in those terms but the actual fans who come from the streets around the grounds. It didn't cross that divide, so Belfast Celtic have to withdraw from the Irish league in the early '20s due to the sheer level of street sectarian violence in Belfast."
By the end of the 1940s, Belfast Celtic had become "one of the greatest club sides Ireland had ever seen, north or south".
"To an extent that is resented," said Michael of Celtic's success, "And that ultimately leads a riot on Boxing Day 1948 in which Jimmy Jones, who was Belfast Celtic's centre forward, a Protestant, was dragged into the crowd by Linfield fans who are all Protestants who jumped on him and had his leg broken. After that match, Belfast Celtic fulfilled their fixtures but they withdrew from football at the end of that season and folded. When you think how dramatic that must have been, that's appalling."
In the full chat, Michael discussed the IFA-FAI split, the overlapping capping of players by both associations, the status of George Best who was once threatened in 1971 and past opportunities at having a unified all-island Ireland national team.
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