....Leader or queen of the first invasion of Ireland in the Mythological Cycle. According to the curious reckoning of the Lebor Gabála [Book of Invasions], an attempt to mix Irish memory with biblical history, Ceasair is a daughter of Bith, a son of Noah, and Birren who escapes to Inis Fáil (Ireland) just before the Flood; she has left her homeland in disgrace because she was denied admission to the Ark.

An alternate version has her as the daughter of Banba, one of the eponymous goddesses of Ireland. She lands in Ireland at Dún na mBarc (Co. Cork) on Bantry Bay with fifty women and three men, forty days before the Flood.

The three men divide the women among them, hoping to populate Ireland. Two of the men, including her helmsman, Ladra, die, leaving the full task to Fintan mac Bóchra, a patron of poets, who feels inadequate to it and flees in the form of a salmon.

Abandoned, Ceasair dies of a broken heart. According to the text, the origin of many obscure place-names may be traced to members of her retinue. Ceasair is sometimes used as a poetic synonym for Ireland.

....These were the second group of Celtic people who settled in Ireland, but they were the first to arrive after the biblical Flood. Not much was written about these people. Partholanians were said to have come to from the west, from the Land of the Dead. They arrived 312 years after Ceasair and her followers.

The Partholanians were named after their leader Partholan, son of Sera, who was the king of Greece. Partholon fled from Greece, after murdering his own father and mother. He had lost his left eye, when he attacked his parents.

Accompanied with his wife Dealgnaid (Dalny) and a group of followers, they reached Ireland, after wandering for seven years.

They had encountered the Fomorians, where they fought a battle. The Partholanians managed to defeat and drive the Fomorians from Ireland. However, Partholon died, after 30 years living in Ireland. The rest of the Partholonians died 120 years later from pestilence. The only survivor of the plague was Tuan, a nephew of Partholon.

This Tuan was the son of Starn and grandson of Sera. Tuan witnessed the arrival of Nemed and his followers, known as the Nemedians, thirty years after the last Partholonian, not counting Tuan.

Tuan kept himself hidden from the Nemedians. When Nemedians were gone from Ireland, Tuan still lived, for many generations. Tuan survived because he was transformed into various animal shapes. First as a stag, then as a boar and later as an eagle. In each form, he witnessed successive early invaders of Ireland.

When he was transformed into a salmon, he was caught one-day, and eaten by the wife of Cairill, who immediately fell pregnant as the result of her meal. She gave birth to a son, who was named Tuan mac Cairill. It was this reborn Tuan, who was said to have the written a book about the early history of Ireland.

....They were possibly nothing more than pirates or raiders, since they never settled in Ireland, and never considered to be Celtic people (Irish). The Fomorians were race of strange beings. The Fomorians were ugly, misshapen giants, who lived on Tory Island. They were cruel, violent and oppressive.

The Fomorians had fought the Partholanians, Nemedians and Tuatha Dé Dananns. For awhile the Fomorians ruled over the Nemedians and the Dananns, extracting tributes and taxes from them. These two groups suffered from the oppression and tyranny of the Fomorians.

Later Lugh Lamfada led the Danann to overthrow the Fomorian oppression. The Tuatha Dé Danann finally annihlated the Fomorians. Balor was their last leader. Lugh would later kill Balor, the hero's grandfather.

....The Nemedians arrived 30 years after the extinction of the Partholanians. They probably come from the west in the Land of the Dead, or else from Spain. This group sailed for a year and half, wandering the sea with a fleet of 32 ships, carrying less than a thousand persons. Only one ship would survive the journey, including Nemed as their leader, and Nemed's four sons.

Nemed was a descendant of Japheth, the son of the biblical Noah. Nemed was married to Macha; a woman associated with Morrígan (Morrigan),from the race called Tuatha Dé Danann.

The Nemedians were the descendants of Nemed and his small group of survivors managed to gradually repopulate the isle. However, the Nemedians also had deadly encounters with the Fomorians, such as the Partholanians did earlier.

Though the Nemedians were at first successful against the Fomorians, with four decisive victories, a pestilence decimated the population, until less than two thousand Nemedians survived.

The Nemedians had to suffer from Fomorian tyranny and oppression, paying heavy tributes to their overlords. Later three Nemedian chieftains led their people in revolt.

They attack the Fomorian stronghold of Tory Island. Though the Nemedians managed to kill one of the Fomorian kings and captured one of the towers, the Nemedians were almost totally annihilated, when the Fomorians received reinforcement. Only thirty Nemedians survived the battle.

These survivors fled from Ireland and the Nemedians as we know them, were never heard from again. Fergus Lethderg fled with his son Britain Máel to Alba (Scotland), where the whole island was named after Britain, Nemed's grandson.

While Semeon son of Erglan son of Beoan son of Starn son of Nemed had fled to Greece, where were subjugated and became slaves. The descendants were known as the Fir Bolg, who would later return to Ireland.

Another group of Nemedians migrated to the islands of Northern Greece. Iobath son of Beothach son of Iarbanel son of Nemed had brought his followers to these islands, where they became known Tuatha De. Later when they migrate back to Ireland, they became known as Tuatha De Danann.

....were actually descendants of the Nemedians, who fled Ireland from both the war against the Fomorians and the plague that ravaged their population. Semion, great-great-grandson of Nemed had brought his followers to Greece, but they suffered from slavery and oppression at the hands of their Greek masters.

It was the five sons of Dela, descendants of Semion, who took his people out of slavery in Greece and Thrace, bringing them back to Ireland, 230 years later.

The sons of Dela (Firbolgs) divided Ireland between themselves, but their power in Ireland only lasted for 37 years before the Tuatha Dé Danann arrived. The Firbolgs were often seen as inferior people, and strangely, quite primitive to the Tuatha Dé Danann, and later the Milesians.

Tailtiu was the daughter of King of the Mag Mor ("Great Plain"), from the Land of the Dead, which was a poetic name for Spain. Tailtiu married to the last Firbolg king, Eochaid Mac Eirc, who died in the First Battle of Moytura. At her husband's death, she married again Eochaid Garb Mac Dúach, a Danann warrior.

Since she was the foster-mother of Lugh, she was held in honour at the Lugnasad by the Tuatha dé Danann.

Not much was known about these people, except with their dealing with other settlers. They did not seem to have any trouble with the Fomorians. The Firbolgs, however did not like the Tuatha Dé Danann, and fought the First Battle of Moytura, before they were defeated. The Firbolgs lost the battle because the Dananns had technologically superior weapons.

The Firbolg warrior Fer Díad, was the companion of Cú Chulainn. He was one of Medb's champions who fought against Cú Chulainn in single combat. Fer Díad was killed after three-days of fighting.

....or the Children of the goddess Danu. They would later become regarded as Celtic deities by the pagan Irish, and as fairies to the Christians.

Like the Firbolgs, the Tuatha Dé Danann were descedants of Nemedians. The Nemedian survivors who followed Iobath son of Beothach son of Iarbonel to the northern isles became known as the Tuatha Dé Danann. Iarbanel was the son of Nemed and a prophet.

The northern isles have four magical, otherworldly cities, each one ruled by a druid. The cities were called Falias, Gorias, Finias and Murias. The Danann learned all sorts of arts and crafts, philosophy and medicine, music and warfare, science and magic. They were scholars, bards, druids, craftsmen, and warriors. The descendants had gained otherworldly powers.

In each city, there was a treasure, a talisman that the Danann would later bring to Ireland in their war against the Fomorians. More information about magic treasures would be found later.

The Tuatha Dé Danann came to Ireland under the leadership of Nuada, a son of Danu. Among the Dananns were also Dagda, Oghma, Goibhniu and Bres. They won the First Battle of Moytura against the Firbolgs, because of their technological superior weapons and magic.

At first, the Fomorians were the Danann's ally before their arrival in Ireland, but later became their deadly enemy. Under the leadership of Lugh, the Dananns also defeated the Fomorians in the Second Battle of Moytura.