This paper argues for a new way of thinking about Early Celtic art in the context of changes taking place throughout Eurasia during the fifth and fourth centuries bce. It applies ideas of anthropologist Alfred Gell, among others, regarding art as a stimulus to action. It asks, in the spirit of papers by Chris Gosden and W.J.T. Mitchell, ‘what did the art do’? The paper argues that this complex new art can be understood in terms of agency contributing to and even stimulating aggressive attitudes and practices on the part of elites during the late fifth and early fourth centuries bce. The new worldviews that are apparent in the new style, and actions driven by them, played major roles in Iron Age Europeans’ participation in the so-called Axial Age of dynamic change throughout Eurasia.