For over 1600 years, the Julian calendar miscalculated the solar year, leading to a ten-day discrepancy affecting religious observances like Easter. The book examines the meticulous calculations made by Pope Gregory XIII's commission to devise a more accurate system. It details the vehement reactions to the new calendar, particularly from Protestant countries that viewed it as a ""Papist plot,"" and traces its eventual worldwide adoption.
Using primary sources and astronomical data, this book offers a balanced perspective on a pivotal moment in timekeeping history. The book begins with historical context, progresses through the scientific basis and social reactions, and concludes with its global implementation. It is a valuable resource for those intrigued by history of science or the sociology of time.