for the change, "England remained outside the Gregorian system for a further 170 years, communications during that period customarily carrying two dates". In contrast, Thomas Jefferson, who lived while the British Isles and colonies eventually converted to the Gregorian calendar, instructed that his tombstone bear his date of birth by using the Julian calendar (notated O.S. for Old Style) and his date of death by using the Gregorian calendar. At Jefferson's birth, the difference was eleven days between the Julian and Gregorian calendars and so his birthday of 2 April in the Julian calendar is 13 April in the Gregorian calendar. Similarly, George Washington is now officially reported as having been born on 22 February 1732, rather than on 11 February 1731/32 (Julian calendar). The philosopher Jeremy Bentham, born on 4 February 1747/8 (Julian calendar), in later life celebrated his birthday on 15 February. There is some evidence that the calendar change was not easily accepted. Many British people continued to celebrate their holidays "Old Style" well into the 19th century, a practice that the author Karen Bellenir considered to reveal a deep emotional resistance to calendar reform. Differences between Julian and Gregorian dates The change arose from the realisation that the correct figure for the number of days in a year is not 365.25 (365 days 6 hours) as assumed by the Julian calendar but slightly less (c. 365.242 days): the Julian calendar has too many leap years. The consequence was that the basis for the calculation of the date of Easter, as decided in the 4th century, had drifted from reality. The Gregorian calendar reform also dealt with the accumulated difference between these figures, between the years 325 and 1582 by skipping 10 days to set the ecclesiastical date of the equinox to be 21 March, the median date of its occurrence at the time of the First Council of Nicea in 325. Countries that adopted the Gregorian calendar after 1699 needed to skip the additional day for each subsequent new century that the Julian calendar had added since then. When the British Empire did so in 1752, the gap had grown to eleven days; when Russia did so (as its civil calendar) in 1918, thirteen days needed to be skipped. Other notations The Latin equivalents, which are used in many languages, are stili veteris (genitive) or stilo vetere (ablative), abbreviated st.v. and respectively meaning , and stili