An interesting study in the Journal of Archaeological Science suggests that Viking intervention through colonisation etc. had an important impact on Ireland’s population.
Over the last twenty to thirty years or so, the actual impact of Viking influence really only started to become recognised and nowadays it’s pretty much accepted that the vast majority of Irish people carry at least a trace of Scandinavian DNA (which must create some interference for those companies selling DNA tests to people who want to prove that they’re ‘physically’ Irish).
Again, its really only in the last few decades that we’ve also started to understand the cultural links as well. A lot of Irish mythological stories have parallels in Scandinavian mythology and often its hard to know which is the chicken and which is the egg (i.e. whether the story started in Ireland and was adapted in Scandinavia or vis versa). Either way, there’s still plenty under the cultural bedcovers that remains to be discovered.
You can find the link here: https://theconversation.com/viking-migration-left-a-lasting-legacy-on-irelands-population-122148?fbclid=IwAR0ajrg7Y1IVRBvdgyUFgjtXu2d2pRfR7SUMsyqZ3XAUQ6NkbnoerqOKOKw