The ancient Celts terrified the Greeks and Romans, but the modern-day revival of Celtic music and art charms millions of people around the world. What makes something “Celtic”? Can we draw any connection between the Gaulish warriors who defied Caesar and the performers of Riverdance?

Modern scholarship has transformed what we thought we knew about the people known to the classical world as the Celts. In examining the complex and fascinating legacy of the Celtic world, historian Jennifer Paxton reveals that the traits we associate with the Celts—their language, their art, and their customs—may not have arisen among a single ethnic group. Rather, these features coalesced among peoples in northwestern Europe, who were pushed to the margins by the Romans and then dominated by the rising nation-states of Britain, France, and Spain.

In the 16th century scholars took new interest the Celtic legacy, and popular culture followed suit, leading to a fascination with Celtic history, literature, and art. The Celtic revival played a vital role in the independence struggle in Ireland and in the rise of cultural nationalism in Wales and Scotland. The obsession with Scottish tartan even extended to the decidedly non-Celtic British royal family.

The term “Celtic Tiger,” used to describe the success of the Irish economy from the 1990s onward, demonstrates how important Celtic identity is to contemporary politics in Ireland. Ironically, the precarious health of the Celtic languages stands in marked contrast to the worldwide popularity of Celtic-inspired music.

Paxton teaches British and Irish history at The Catholic University of America, where she is a clinical assistant professor of history and director of the university honors program.