A term used to describe the
Celts, a group of related ethnic groups who migrated into Europe around 1000 BC, and the languages and cultures which have their origin in these people.
The Celts or Gauls slowly migrated across Eastern and Western Europe, and descendants of the Celts were either eliminated or assimilated by the Romans. Today, all the surviving cultures and languages that can trace their roots to the Celts are found in extreme northwest Europe, where they generally exist as minorities in larger nations.
During the 19th century, nationalist groups in Great Britain and France took on the mantle of "Celtic" culture as a way to unify their various movements and to indentify themselves with a unique and proud history. A mythology of "Celtic" tradition was particularly popular in Victorian England.
Much of what we now think of as "Celtic" is a creation of 19th-century romanticism--and almost nothing in our popular image of Welsh and Irish culture can be directly traced back to the culture of the Celts who founght Julius Caesar back in the 1st century BC.