Ancient physicians and philosophers explored how different temporal patterns interacted and overlapped. They were deeply concerned with the meaning of simultaneous events—those moments when natural, bodily, or social processes coincided in ways they considered significant. While Greek and Latin authors had no direct equivalents for what we now call “synchronicity” or “synchronization”, both ideas permeate their reflections on health and the cosmos. This volume adopts these modern terms as a framework for examining how Greco-Roman thinkers conceptualized meaningful coincidence and the effort to align temporal cycles—between body and environment, illness and therapy, or individual and world. Spanning medicine, philosophy, astrology, and meteorology from the fifth century BCE to the sixth CE, the chapters reveal how ancient conceptions of bodily time and cosmic rhythm shaped understandings of health, gender, and disease. By tracing these interconnections, the volume opens new perspectives for scholars of ancient science, philosophy, and culture about the roles of synchrony and asynchrony in understanding and intervening in bodily processes.