Pope Gregory IX King Greg I Lord Gregg Pope Gregory XIII
75 15 95 60
200 20 2000 40
49 99 19 89
900 90 1100 150
St Bede Kepler St Greg Assisi
202 20002 222 2002
3 days every century 1 day per year 6 days every century 3 days every 400 years
900 400 1100 600
Feb Jul Oct Nov Apr Jun Sep Nov Mar Jul Oct Dec Jan Apr Sep Dec