Brennus or Brennos is the name of two Gaulish chieftains, famous in ancient history: The linguistic origins of the name are unclear, despite two theories linking it to Welsh words.
Despite suggestions by scholars as early as the 12th century AD, including one by Geoffrey of Monmouth in his Historia Regum Britanniae, Brennus is not likely to share a common origin with the Welsh personal name Bran (or Brân) meaning "crow"; the similarity of the names is deemed to be superficial.
However, despite assertions by some 19th-century scholars, Brennus and the modern Welsh word for "king", brenin (earlier breenhin) are not related.
[1] Brenin is instead derived from the Celtic *brigantinos, meaning "(someone) pre-eminent, outstanding".
[2] Variants and adaptations of the name may include: