The Invaders

Who were these new invaders to Ireland?

The second third of modern Irish DNA is composed of two distinct waves of Celtic migration (KEL-tik, not CELL-tik). These Caucasian (pale-skinned humans originating Caucasus Mountains of the central high Asian steppes around 12,000 years ago according to population geneticists) Ind0-European people (ancient groups who spoke Indo-European languages and spread across Europe and Asia, beginning around 4000–2000 BCE) were named by the Greeks (whose culture and language also came from the Indo-European ANF people) for their culture and language which was different from theirs, and their word Keltoi (Κελτοί) likely meaning foreigners but could also mean the hidden people of Central Europe. The Romans would call them the Gallus, their province Gallia, also meaning foreigner but could come from a lost ancient Celtic word for strong people. They were cousins linguistically and genetically to the Greeks and the Romans, but distinctly different in language and custom that they were not understood to be so, but rather some strange foreign people, distinct from their other cousins, the Germanic tribes of northern European forests.

The second 1/3 of Irish DNA is from two distinct waves of Celtic Migration.

The last third of modern Irish DNA can be traced to a later wave of Indo-European people—this time not Celtic-speaking (Irish Goidelic, Scottish Gaelic, Welsh/Brittonic Byronic/Brittonic), but Germanic-speaking—known to history as the Vikings. These sea-faring raiders and warriors came from Scandinavia, beginning around 795 CE, when the first recorded Viking raid struck Lambay Island, just north of modern-day Dublin. From the late 8th to the 11th centuries, Norse invaders launched a series of attacks, settlements, and trading outposts along the Irish coast, especially in the east, northeast, and southeast regions. Cities such as Dublin, Waterford, Wexford, Limerick, and Cork began as Viking longphorts (fortified ship-camps). Genetic and archaeological evidence suggests that Celtic-speaking peoples reached the British Isles in two major waves: the first entered southern Britain from the European mainland across the English Channel, likely during the Bronze Age (around 2000–1500 BCE), and a second wave expanded into Ireland and western Britain during the Iron Age (roughly 500–100 BCE).

The third 1/3 of Irish DNA is from Norse or Viking invasion and settlement in Ireland (more prominent in the northern and eastern parts of Ireland).

Sources:

The “Radiant" Tuatha De Dannon

(TOO-uh-huh DAY DAH-nun or TOO-a DAY DAH-nun)

The First (Tuatha) Celtic Wave

Tuatha Dé Danann means “The Tribes (or People) of the Goddess Danu.” Around 3000 BCE, the first Indo-European-speaking people entered Ireland. They likely came from northwest France, crossing through Britain after crossing the English Channel between. They then migrated by land and boat through Scotland.

They were fair-skinned, spoke an early Celtic language, and used bronze tools.

These people are remembered in Irish mythology as the Tuatha Dé Danann, the children of the goddess Danu, who defeated the Fomorians and brought new culture and order. Irish mythology may cryptically (concealment, hidden) record the history of the Celtic invasion of Ireland and dis- or re- placement of the native, dark Irish by Celts.

The Tuatha Celtic migration is associated with La Tène Culture, a classic flowering of Celtic art, warfare, and society that followed the earlier (continental European) Hallstatt culture.

The early Celtic-speaking peoples were part of the Indo-European migrations that began around 3000–2500 BCE, when steppe herders from the region north of the Black Sea (often linked to the Yamnaya culture or horse-cart agro-pastoralist culture) began moving westward into Europe. According to both archaeological finds and population genetics, these migrating groups brought with them new technologies like wagons, horse domestication, and a pastoralist lifestyle, but gradually adopted farming from the Neolithic peoples they encountered. Their descendants formed the Corded Ware and Bell Beaker cultures, which spread across central and western Europe, and over time gave rise to the Urnfield and Hallstatt cultures, considered the heart of early Proto-Celtic civilization.

These migrations layered atop earlier populations, blending with existing Neolithic and Copper Age communities. Unlike the earlier farming groups that came to Ireland via the Celtic Sea from Brittany or Spain, these later Celtic arrivals followed the more familiar Channel and land route through Britain, bringing with them the languages and cultural traditions that would later shape Goidelic Ireland.

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The Sons of Conquering Warrior Mil Espáine

The Second (Milesian) Celtic Wave

Mic Míl Espáine means “The Sons of Míl of Spain." Around 1000 BCE, a second Celtic wave arrived in Ireland, this time from northern Spain’s Basque region.

These Celts used iron tools and established tribal kingdoms. Modern Irish men with Gaelic surnames often carry haplogroup Rb1 L21 subclade, a genetic marker linked to this migration.

In mythology, they are called the Milesians, said to have conquered the Tuatha Dé and become the final human settlers as the sons of the conquering warrior king Míl Espáine.

Interestingly enough, Spanish Basques share DNA with Irish men descending from these lines—seeming proof of the historicity of Irish pseudohistory possibly embedded (or recently reimagined) in Irish mythology and storytelling.

In mythology, heroic figures from the past sometimes become deified (turned into gods) or remembered as legendary heroes who are worshipped.

For example, the Greek warrior Achilles, who fought in the Trojan War, may have been based on a real person. A theonym (a god-name) linked to Achilles has been found near Mycenae, which may be an early sign that he was once a real person. Later, Greek city-states claimed they were related to heroes like Achilles and Hercules, treating them like real people—not just legendary hero archetypes (famous examples that show what a hero is like). In Egypt, a king named Thoth from the Old Kingdom was later turned into a god during the New Kingdom. He became the God of Wisdom, Writing, and Knowledge.

Because of stories like these, folklorists and cultural anthropologists believe that the Tuatha Dé Danann—the supernatural beings who defeated the sea demon Fomorians in Irish myth—might also represent the “founding fathers” of the Celtic people who came to Ireland and them displacing and replacing the dark Irish natives — recording the conquest of Ireland.

Sources:

Milesian Red Hair R1b vs Indo-European R1b

Celtic-surnamed Irish males and their association with the L21 subclade of the R1b genetic marker associated with red hair are different from the M269 subclade of the R1B which all Indo-European people share.

The Heathen Beast Viking Invaders

The Last Wave of Invasion (before the Scotch-English in the modern Era)

Between 800 and 850 CE, Norse (Viking) invaders reached Ireland. They founded coastal settlements and introduced new technologies. Their genetic influence is still present, especially in coastal populations

In annalistic sources like the Annals of Ulster, Annals of the Four Masters, and Cogadh Gaedhel re Gallaibh, the Vikings are described as “foreigners,” “heathens,” “dark invaders,” and “sons of destruction.” Irish mythology and folklore echo this portrayal, often casting them as beast-like, monstrous, or fair-haired outsiders who came from the sea bringing chaos and violence, but also strange knowledge and foreign wealth. Over time, some Norsemen integrated into Irish society, forming hybrid groups like the Hiberno-Norse, and their genetic legacy is strongest in eastern coastal regions and parts of the north, particularly around Dublin Bay and Louth.

Despite their fearsome reputation, the Norse also brought maritime technology, urban trade networks, and new cultural practices that reshaped early medieval Ireland. Today, DNA studies confirm that a significant portion of Irish ancestry—especially in the eastern third of the island—derives from these Germanic Scandinavian invaders, whose language, burial customs, and surnames left an enduring mark on Ireland’s people and place-names.

Timeline of arrival:

795 CE: First raids (Lambay Island, Rathlin, etc.)
841 CE: Permanent longphorts in Dublin and Annagassan
1014 CE: Battle of Clontarf marks turning point

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“Irish" Red Hair: False Tales

Ask anyone where red hair comes from, and they'll probably say Ireland or Scotland. They're right. It's Celtic. Even the Romans described red-headedness among the Celts, and it did originate in Ireland and Scotland.

But thanks to the internet and profit-motivated sensationalism, many have come to believe it originated with the Viking raids, and dispersed through viking rape. As the raiding Norse often killed the native men, raped their widows, and sold their children into slavery while taking any valuables when “sacking" a city, they spread these genes. But it turns out this genetic change is Celtic, not Norse.

Relative Deep Time: Early Civilizations Begin

Sumerians in Mesopotamia develop writing (cuneiform) – one of the world’s first written languages.
First cities like Uruk and Eridu flourish in Sumer (Iraq).
Egypt unites under King Narmer (Menes), starting the First Dynasty (Old Kingdom) and building early pyramids.
Harappan (Indus Valley) civilization rises in modern Pakistan/India, known for city planning and sanitation.
Stonehenge’s earliest phase is constructed in Britain.
Bronze Age begins in many areas—people begin using bronze tools and weapons.
Neolithic farming spreads throughout Ireland—megalithic complexes like Newgrange and Carrowmore are fully built at the start, and new passage tomb burial mounds are built across Ireland

Relative Deep Time: Kingdoms & Empires Form

King David rules Israel, uniting the Hebrew tribes (according to the Bible).
Iron Age begins across the Mediterranean and Europe—iron tools replace bronze.
Greek city-states (like Athens and Sparta) begin to develop independently.
Phoenicians spread across the Mediterranean, creating alphabet writing systems.
Assyrian Empire rises in Mesopotamia, conquering Sumer, and known for military power.
Olmec civilization flourishes in Mesoamerica (Mexico), creating giant head sculptures.
Zhou Dynasty rules China, replacing the Shang, and introduces the Mandate of Heaven idea.

Relative Deep Time: Medieval Period Powers and Cultures [Middle Ages, 476-1500 CE, 476-1000 CE “Dark Ages or Early Middle Age" ]

Charlemagne is crowned Emperor of the Romans in 800 CE, reviving the Holy Roman Empire in Europe.
Vikings raid Lindisfarne, England, the holy island (793 CE) and continue attacking across Europe during this period.
The Abbasid Caliphate controls much of the Islamic world—Baghdad becomes a center of science and learning.
Tang Dynasty rules China, expanding trade on the Silk Road and spreading Chinese culture.
Maya cities in Central America begin to decline, possibly from drought and warfare.
Alfred the Great is born (849 CE), who will later defend Anglo-Saxon England from Vikings.
Irish monasteries preserve classical knowledge, producing illuminated manuscripts like the Book of Kells.

Left: A map of the frequency of red hair by population in modern Europe.

Right: A map of the genetic distribution of the R1B L21 subclade associated with the Milesians. It may have been selected in Celtic populations because of sexual selection (females or males preferred mates with red hair) or adaptive due to its association with even fairer skin which would allow more Vitamin D at higher latitudes.

Source: Eupedia.com: The genetic causes, ethnic origins and history of red hair👈

*DISCLAIMER: Interpretive Mythology & Migration Theory

This section draws on the idea that Irish mythology, though symbolic and mythological, may reflect actual prehistoric migrations.

While these associations are interpretive and not entirely proven through archaeology, many folklorists and cultural anthropologists believe that works like the Lebor Gabála Érenn (The Book of Invasions, LYEV-ur guh-BAWL-uh AIR-en or LYEV-ur guh-BAWL-uh EH-ren) encode collective cultural memory of real population shifts (Irish prehistory, or the time before the Irish kept written records).

These figures—Fir Bolg, Fomorians, Tuatha Dé Danann, and Milesians—are mythological, but may correspond to remembered or reimagined prehistoric groups.

For further reading:

- Lebor Gabála Érenn – Wikipedia Overview👈

- Mythological Cycle – Irish Euhemerism👈

- John Carey’s The Irish National Origin-Legend: Synthetic Pseudohistory👈

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Pomonalia and Nut and Apple Traditions, the Attempted Roman Extermination of the Celtic Druids in Britain, Continued Survival of Celtic Druidic Religion in Ireland, & How Halloween First Became Associated with Devil Worship by Christian Slanders & Sloppy Scholarship