How many times a day do you check your calendar or look at your clock? In this modern age, our lives are driven by deadlines, schedules and timetables. Time and its many divisions (hours, days, weeks, months and years) have completely shaped our lives and yet it’s rare that we take the time to think about where these concepts arise from. The calendar as we know it is inextricably linked to the mechanics of our solar system, and the way in which we describe our periods of time have arisen from ancient speculation in astronomy, mathematics and religion. In this talk, Donna will provide a brief history of our calendar and an introduction to time measurement from ancient sundials to modern atomic clocks.