Tracing the Spread of Celtic Languages using Ancient Genomics

Celtic languages, including Irish, Scottish Gaelic, Welsh and Breton, are today restricted to the Northern European Atlantic seaboard. However, between 3 and 2 thousand years before present (BP) Celtic was widely spoken across most of Europe. While often associated with Bell Beaker-related populations, the spread of this prominent Indo-European linguistic cluster remains debated[1][1]–[7][2],. Previous genomic investigations have focused on its arrival to specific regions: Britain[8][3], Iberia[9][4] and Southwestern Germany[10][5]. Here, we utilize new genomic data from Bronze and Iron Age Europe to investigate the population history of historically Celtic-speaking regions, and test different linguistic theories on the origins and early spread of the Celtic languages. We identify a widespread demographic impact of the Central European Urnfield Culture. We find ancestry associated with its Knovíz subgroup in the Carpathian Basin to have formed between 4 – 3.2 kyr BP, and subsequently expanded across much of Western Europe between 3.2 and 2.8 kyr BP. This ancestry further persisted into the Hallstatt Culture of France, Germany and Austria, impacting Britain by 2.8 kyr BP and Iberia by 2.5 kyr BP. These findings support models of an Eastern Central rather than a Western European center of spread for a major component of all the attested Celtic languages. Our study demonstrates, yet again, the power of ancient population genomics in addressing long-standing debates in historical linguistics. ### Competing Interest Statement The authors have declared no competing interest. [1]: #ref-1 [2]: #ref-7 [3]: #ref-8 [4]: #ref-9 [5]: #ref-10

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Exploring the Demographic Spread of the Central European Urnfield Culture and Celtic Languages

Introduction

The Urnfield Culture, renowned for its widespread influence during the Late Bronze Age, represents a pivotal chapter in European prehistory. Originating from Central Europe, this culture spread across the continent between approximately 3,200 and 2,800 years ago, leaving a rich archaeological imprint that continues to intrigue scholars today. Recent genomic research has revealed the crucial role this culture played in the spread of Celtic languages across Europe.

The Origins and Expansion of the Urnfield Culture

Central European Roots

The Urnfield Culture emerged in Central Europe and is primarily known for its distinctive cremation practices—a shift from traditional burials that suggests significant social evolution. This cultural transition is marked in the archaeological record by cremated remains placed in urns within large cemeteries, hence the culture's name.

The Knovíz Connection

One of the more intriguing facets of the Urnfield Culture's spread is the role of its Knovíz subgroup. Genetic evidence traces Knovíz ancestry back to the Carpathian Basin, from where it gradually swept across Western Europe. Archaeological sites associated with the Knovíz Culture reveal captivating insights into:

• Advanced metallurgical practices
• Settlement expansions
• Cultural and agricultural innovations

Geographic Expansion

The Urnfield Culture's influence extended far beyond its Central European origins:

• Westward into France, Germany, and Austria
• Northwest to Britain
• Southwest to the Iberian Peninsula

This expansion laid the groundwork for the later Hallstatt Culture, which is often associated with the early Celts.

Cultural and Technological Innovations

Agricultural Advancements

The innovations of the Urnfield Culture were not confined to burial practices and settlement patterns. Advances in agriculture, including the cultivation of millet, catalyzed demographic changes and population growth across Europe.

Metallurgical Expertise

Improved metal craftsmanship was another hallmark of this culture. The exchange of commodities such as bronze, salt, and other raw materials facilitated the Urnfield Culture's reach and prosperity, creating extensive trade networks throughout Europe.

Conflict and Competition

Not all expansion was peaceful. The Tollense Valley in Northern Germany reveals evidence of an ancient battlefield dating back to around 3,200 years ago, indicating dramatic confrontations as the Urnfield Culture tried to extend its influence northward. This battle marks a period of turbulence and territorial disputes, likely shaping the trajectory of cultural dispersals in the region.

The Celtic Language Connection

From Urnfield to Celtic Languages

Current Celtic languages like Irish, Scottish Gaelic, Welsh, and Breton are now confined to Europe's western fringes, but between 3,000 to 2,000 years ago, Celtic languages were spoken across much of the continent. Genomic research has now provided compelling evidence linking the spread of these languages to the expansion of the Urnfield Culture.

Archaeological Evidence

Key archaeological sites have been crucial in understanding these connections:

• Hallstatt in Austria: Known for its salt mines and vivid cultural artifacts, this site highlights the genesis of Celtic ancestry
• Únětice in the Czech Republic: Provides insights into Bell Beaker influence and cultural mixing
• Golasecca Culture in Northern Italy: Reveals connections between Celtic artifacts and the mysterious Lepontic dialect

Bell Beaker Foundation

The Bell Beaker Culture, which preceded the Urnfield period, laid important foundations for later developments. Their distinctive pottery often accompanies graves of these ancient peoples, and their genetic signature—a blend of Steppe and local ancestries—suggests they played a crucial role in spreading Indo-European dialects across Europe.

Genomic Insights

Tracing Migration Through DNA

Using techniques such as IBD (Identity By Descent) Mixture Modeling, researchers have tracked the fine fabric of human migration across Bronze and Iron Age Europe. The genomic data reveals:

• Bell Beaker populations with their unique genetic blend carried early Indo-European dialects to diverse corners of Europe
• Urnfield populations, particularly the Knovíz subgroup, spread their genetic and likely linguistic influence from France to Southeast Europe
• British populations experienced dramatic genetic shifts around 4,500 years before present, with later Urnfield influence arriving around 2,800 years ago

Challenges in Research

The Urnfield period presents unique challenges for genetic research due to widespread cremation practices, which often destroy DNA. However, insights have been gleaned from:

• Inhumation burials that occurred alongside cremations
• Earlier and later populations genetically linked to Urnfield groups
• Cultural artifacts and grave goods that provide context for genetic findings

Cultural Legacy: From Urnfield to Hallstatt and La Tène

Cultural Evolution

As descendants of the Urnfield Culture, the Hallstatt and La Tène Cultures reflect a rich tapestry of cultural evolution. These later cultures took the foundations established by their ancestors and developed them into the historically documented Celtic presence across Europe.

Material Culture

Grave goods unearthed from tombs tell silent stories of migrations and cultural connections:

• Sophisticated metalworking in bronze and later iron
• Distinctive pottery and jewelry styles
• Weapons and warrior equipment suggesting social hierarchies

Linguistic Diversity

The diverse pockets of Celtic languages that once spanned Europe—such as Lepontic in the Alps and Celtiberian in Iberia—map onto these genomic stories. Each dialect represents a testimony of migration patterns and cultural intermingling.

Conclusion

The genomic evidence now paints a compelling picture of how the Urnfield Culture, especially its Knovíz subgroup, played a crucial role in spreading the ancestors of Celtic languages across Europe. This prehistoric expansion helped shape the cultural and linguistic landscape of Iron Age Europe, setting the stage for the Celtic societies later encountered by classical writers.

While Roman expansion would eventually overshadow earlier Celtic dominance, the intricate tapestries woven by these early Indo-European tongues left an indelible mark on European history. Modern genomic research continues to refine our understanding of these ancient migrations, revealing how interconnected the peoples of prehistoric Europe truly were.