 In the middle of the fifth century BCE, Empedocles of Acragas formulated a philosophical program in hexameter verse that pioneered the influential four-part theory of roots (air, water, earth, and fire) along with two active principles of Love and Strife, which influenced later philosophy, medicine, mysticism, cosmology, and religion. The philosophical system responded to Parmenides’ rejection of change while embracing religious injunctions and magical practices. As a result, Empedocles has occupied a significant position in the history of Presocratic philosophy as a figure moving between mythos and logos, religion and science. Modern debate arises from the lack of consensus on the number of his verse works, their relation to one another, and the coherence of his philosophical system as a whole. This entry will introduce Empedocles, his life and work—traditionally referred to as On Nature and the Purifications—as well as the scholarly debates that continue to dominate study of his philosophical system. It closes with the influence Empedocles had upon his successors. The numbering of the fragments in this article follows that of the Diels-Kranz edition [DK] and Laks and Most 2016; translations are from Laks and Most.