Eigyr is the original Welsh form of the name Igraine, which appears in the Arthurian cycle. In the Matter of Britain, Eigyr (Middle Welsh Eigyr, modern Welsh Eigr) is the mother of King Arthur by Uther Pendragon and the wife of Gorlois, Duke of Cornwall. Her historical depiction originates in Geoffrey of Monmouth's 12th-century work Historia Regum Britanniae, where she is called Igerna. The name subsequently evolved into the more familiar Igraine in later French and English romances.
Etymology
The exact meaning of Eigyr is unknown. It is derived from the Latinized form Igerna, which itself was based on the earlier Welsh name Eigyr (or Eigr). There are no secure etymological connections to other Celtic elements, though the name is firmly tied to Arthurian legend through its role in naming Arthur's mother.
Legendary Background
According to Arthurian legend, after Gorlois's death, Uther Pendragon — with the help of Merlin's magic to assume Gorlois's shape — lay with Igraine, resulting in the birth of Arthur. In later versions, such as Thomas Malory's Le Morte d'Arthur, Igraine is also the mother of Morgan le Fay, Morgause, and Elaine by Gorlois. Thus, she links Arthur to several key figures in the mythology. The character's role is foundational, establishing the lineage of the legendary king.
Cultural Significance
Eigyr's name survives primarily as a historical and meta name — that is, a Welsh variant rather than a commonly used given name in modern Wales. Its legendary prestige keeps it alive in onomastic and literary studies, especially in connection to Arthurian traditions.
Sources: Wikipedia — Igraine