The Baiuvarii or Bavarians (German: Bajuwaren) were a Germanic people. The Baiuvarii had settled modern-day Bavaria (which is named after them), Austria, and South Tyrol by the early 5th century AD, and are considered the ancestors of modern-day Bavarians and Austrians. The Baiuvarii spoke the early Bavarian language.
The name of the Baiuvarii is also spelled Baiuvari. It probably means "men from Bohemia". The placename Bohemia is believed to be connected to that of the Boii, a Celtic people who left the region before the Roman era and were replaced by Germanic peoples. The Baiuvarii gave their name to the region of Bavaria.
The name is first attested in Latin sources in the 6th century AD. In the Getica (551), Jordanes writes that a group of Suebes near the Danube were neighbored on the east by the Baibari. In a poem about a pilgrimage to Augsburg in 565, Venantius Fortunatus writes that the Baiovarius lived in area around the river Lech called Baiuaria.
The Baiuvarii are classified as a Germanic people. It is uncertain whether they originally spoke an East Germanic or West Germanic language. Early evidence on the language of the Baiuvarii are limited to personal names and a few Runic inscriptions. By the 8th century AD, the Baiuvarii were speakers of an early form of the Austro-Bavarian language with the West Germanic family.
Evidence from etymology traces the history of the Baiuvarii back to Bohemia in the 1st century AD. This was after the Celtic Boii left the area and were replaced by Maroboduus, king of the Germanic Marcomanni, who moved his Suebian people into the area. Whether the Baiuvarii settled Bavaria in a specific later migration, after Maroboduus, either from the north (Bohemia) or from Pannonia, is now uncertain.
According to Karl Bosl, Bavarian migration to present-day Bavaria is a legend. The early Baiuvarii are often associated with the Friedenhain-Přešťovice archaeological group, but this is controversial. During the time of Attila in the 5th century the entire Middle Danube region saw the entry of many new peoples from north and east of the Carpathians, and the formation and destruction of many new political entities.
It is thus more probable that the Baiuvarii emerged in the provinces of Noricum ripense and Raetia secunda following Odoacer's withdrawal of population to Italy in 488, and the subsequent expansion of Italian Ostrogothic, and Merovingian Frankish influence into the area. They are believed to have incorporated elements from several Germanic peoples, including the Scirii, Heruli, Suebi, Alemanni, Naristi, Thuringi and Lombards. They might also have included non-Germanic Romance people.
One of the earliest references to the Baiuvarii is the Frankish Table of Nations from about 520. By the late 5th century, the region was under the influence of the Ostrogothic Kingdom of Theodoric the Great. During this period, the Frankish king Theudebert I (died 548) claimed control from the North Sea to Pannonia. After his death, his uncle Chlothar I appointed Garibald I as dux of Bavaria. He established the Agilolfings dynasty with his power base at Augsburg or Regensburg. By the 8th century, many Baiuvarii had converted to Christianity.
A collection of Bavarian tribal laws was compiled in the 8th century. This document is known as Lex Baiuvariorum. Elements of it possibly date back to the 6th century. It is very similar to Lex Thuringorum, which was the legal code of the Thuringi, with whom the Baiuvarii had close relations.
The funerary traditions of the Baiuvarii is similar to those of the Alemanni, but quite different from those of the Thuringi. The Baiuvarii are distinguished by the presence of individuals with artificially deformed craniums in their cemeteries. Although, these individuals were predominantly female, only found in small numbers, and they did not leave a genetic impact upon the Bavarian people. Likewise, they were determined to have mostly come from southeastern Europe, perhaps as a form of exogamy.
A genetic study published in the Proceedings of the National Academy of Sciences of the United States of America in 2018 examined the remains of 41 individuals buried at a Bavarian cemetery ca. 500 AD. Of these 11 whole genomes were generated. The males were found to be genetically homogeneous and of north-central European origin. The females were less homogeneous, particularly those with artificially deformed craniums. The vast majority of the surveyed individuals, particularly the males, were predicted to have had blond hair and blue eyes. No admixture with earlier Roman populations of the area was detected. Among modern populations, the surveyed individuals were found to be most closely related to modern-day Germans. This study suggests that Germanic tribes were indigenous to the area of southern Germany. 
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- Fries-Knoblach, Janine; Steuer, Heiko (2014). "Introduction". In Fries-Knoblach, Janine; Steuer, Heiko; Hines, John (eds.). The Baiuvarii and Thuringi: An Ethnographic Perspective. Boydell & Brewer Ltd. pp. 1–10. ISBN 9781843839156.
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- Hammer, Carl I. (2007). From Ducatus to Regnum: Ruling Bavaria under the Merovingians and Early Carolingians. Brepols.
- Haubrichs, Wolfgang (2014). "Baiovarii, Romania, And Others". In Fries-Knoblach, Janine; Steuer, Heiko; Hines, John (eds.). The Baiuvarii and Thuringi: An Ethnographic Perspective. Boydell & Brewer Ltd. pp. 23–82. ISBN 9781843839156.
- Veeramah, Krishna R. (March 27, 2018). "Population genomic analysis of elongated skulls reveals extensive female-biased immigration in Early Medieval Bavaria". Proceedings of the National Academy of Sciences of the United States of America. National Academy of Sciences. 115 (13): 3494–3499. doi:10.1073/pnas.1719880115. PMC 5879695. PMID 29531040. Retrieved March 14, 2020.
- Fries-Knoblach, Janine; Steuer, Heiko; Hines, John, eds. (2014). The Baiuvarii and Thuringi: An Ethnographic Perspective. Boydell & Brewer Ltd. ISBN 9781843839156.
- Media related to Bavarii at Wikimedia Commons