Invasions in Irish mythology is way different from what is generally perceived by people. Before the Gaels arrived in Ireland, five waves occurred that make up the mythological history of the Celts. The invasion waves were never written down but were rather recited orally for generations. Therefore, there is many discrepancies in the facts behind the events. The tales about the five waves were written in 1100AD. However, this gave room for information that has been diluted over time. There is a lot of magic and myth that comprises of the written stories. However, this is because of the dilution that occurred over time. The good news is that there is an element of truth that is hidden which can be inferred by reading and understanding the text from a knowledge perspective.
The Partholan Wave
The leader Partholan was the reason behind the naming convention of this wave. The leader was not a very good man and was responsible for killing his parents and destroying everything that was related to his home before arriving in Dublin. The main rivals of the Partholanians were called the Fomorians. However, in due course, the Partholanians drove the Fomorians out of the land. The tenure of the Partholanians was short lived as they were all destroyed by the plague after 40 years since they arrived in Ireland.
The Nemedian Wave
The leader responsible for the wave was called Neimheahd. He was responsible for leading his people from Scythia to Ireland. During their long travel from Scythia, most of the crew were dead. Over time, the number of Nemedians grew steadily, and they were able to conquer the Fomorians several times. However, the Nemedians were also killed due to the plague after which the Fomorians came back to power. At the end of the wave, the Nemedians were deduced to just three chefs who were driven out of Ireland.
The Fir Bolg Wave
Two hundred years after the Nemedians left Ireland, the third wave arrived in Ireland. The legend has it that Fir Bolg were all slaves who had escaped from Greece and came to Ireland to introduce agriculture. Law and social institutions were introduced to the country as a result of the Fir Bolg. They carried leather bags which is what gave them their name. These leather bags were filled with earth from some of the most fertile valleys of Greece. Some part of the mythology suggests that the Fir Bolg hailed from Spain and not Greece. The group was not strong with military skills as they were most involved in agriculture. Therefore, they were easily defeated at the very first battle they fought.
Thuatha De Danann Wave
Mythology has it that this invasion was by a group that came from the dark clouds. They are also said to have magical controls and stood over Ireland for several years. Just like the other invaders who came, their greatest fight as against the Fomorians. They were quickly able to subdue the Fomorians as well. The Danann who was well known for bringing magic to Ireland and brought The Spear of Lugh, The Dagda’s Cauldron, The Stone of Fal and The Sword of Light of Nuada, in the form of stories to Ireland. The Milesians overthrew them.
The Milesian Wave
The last to arrive were the Milesians. They were Celtic and came to Ireland from the central regions of Europe. Ith who saw the coast of Ireland from Spain vowed to conquer it and achieved it as well. Ith timed his attack, but he was defeated. There was a significant battle that took place where the Danann were defeated but signed an agreement that the Danann would rule from the spiritual realm while the Milesians ruled Ireland from a physical realm.