The Celtic Tribes of Ireland formed as celts immigrated from mainland Europe and British Isles and formed tribes. Later they began interaction and trade as they spread out and populated OTL Ireland, the eastern and southern tribes kept a loose confederacy of trade and alliance. In 215 many of them formed an alliance and waged a war to acquire land, specifically from the northern tribes. The winner being the larger and more united southern and eastern tribes. Forced the northern tribes and leader VERCINGETORIX NYNNIAW to be sacrificed and they set him asail to the north. Little did BRADÁN SLUAGHADHÁN and the tribes know, they would land in OTL Iceland in the spring of 214BC and set up a Celtic advanced tribal nation in OTL Iceland.