Steve Tonkin has been an amateur astronomer since childhood. He has taught astronomy for over 30 years and written many articles and books. He is a Fellow of the Royal Astronomical Society. Referring to the talk Time and Calendars Steve says “The measurement of time has always been a facet of Astronomy. The phases in the development of the Gregorian calendar most of us use today make a fascinating story which blends science, history, sociology, religion and psychology.”