It's widely known that the match at Lansdowne road was hijacked by an organised hooligan element. Due to the close proximity of the 2 countries, it was very easy to organise and fairly cheap for these people to congregate. Only problem was, they couldn't find anyone to fight. This was a culture clash in many ways, because that sort of thing doesn't exist in Ireland. People don't get into scraps watching sport. In many ways, this incident was a throw back to an bygone era, and many of those people who tried to cause trouble will be in their 60's now.
It is very rare to see violence in an English football stadium now.