The Julian calendar, named for Julius Caesar, had been in use for more than 1,500 years. The Julian year was 365 days and 6 hours — 11 minutes and 14 seconds longer than the time Earth actually takes to revolve around the sun. Over the years those minutes and seconds added up, so by a.d. 1580 the vernal (spring) equinox was actually occurring ten days later than the date shown on the calendar. Taking the advice of astronomers, Pope Gregory XIII corrected the difference by dropping ten days and making some adjustments to the leap year with its additional day in February. In 1582, the Pope’s Gregorian calendar was adopted by most Roman Catholic countries in Europe. German states kept the old calendar until 1700, and Great Britain and the American colonies did not change until 1752. Russia and Turkey were the last to accept the new calendar, in 1918. During Anastasia’s time, the difference between the old Julian calendar and the new Gregorian calendar had increased to thirteen days.
