Ireland in the eighteenth and nineteenth centuries was home to rural factions or “fighting gangs” such as the Caravats and the Shanavests. These factions would stage huge battles with the shillelagh, the traditional Irish fighting stick, as the primary weapon.
If you read older histories of ancient Ireland, you might think the country was governed by a highly organized feudal system of high kings, regional kings and tribal kings. That's because most of the older histories took some of their sources too literally, accepting their picture of a highly structured society. The reality was not quite so organized.
When Christianity came to ancient Ireland, what happened to the druids? They can't just have been wiped out, because there was no centralized state power structure that could do such a thing, and in any case the Irish conversion was largely peaceful.
What languages are spoken in Ireland? Well, there's Irish (a Gaelic language), English (a Germanic language with a lot of Latin and French mixed in), and Hiberno-English (a dialect of English with some Gaelic elements mixed in). There also used to be a language called Yola, which was spoken in parts of County Wexford until the nineteenth century.