However, the two events were combined in the late 18th century, and continue to be celebrated into modern times as "The Twelfth".Because of the differences, English people and their correspondents often employed two dates, dual dating, more or less automatically.There is some evidence that the calendar change was not easily accepted. It is common in English language publications to use the familiar Old Style and/or New Style terms when discussing events and personalities in other countries, especially with reference to the Russian Empire and the very-early Russian Soviet.
In Scotland, the legal start of the year had already been moved to 1 January (in 1600), but Scotland otherwise continued to use the Julian calendar until 1752. But the start of the Julian year was not always 1 January, and was altered at different times in different countries (see New Year's Day in the Julian calendar). This was 25 March in England, Wales and the Colonies until 1752.For this reason, letters concerning diplomacy and international trade sometimes bore both Julian and Gregorian dates to prevent confusion: for example, Sir William Boswell writing to Sir John Coke from The Hague dated a letter "12/22 Dec. In his biography of Dr John Dee, The Queen's Conjurer, Benjamin Woolley surmises that because Dee fought unsuccessfully for England to embrace the 1583/84 date set 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 during the time that the British Isles and colonies eventually converted to the Gregorian calendar, instructed that his tombstone bear his date of birth using the Julian calendar (notated O. for Old Style) and his date of death using the Gregorian calendar.For a more general discussion of the equivalent transitions in other countries, see Adoption of the Gregorian calendar. There were two calendar changes in Great Britain and its colonies, which may sometimes complicate matters: the first change was to change the start of the year from Lady Day (25 March) to 1 January; the second was to discard the Julian calendar in favour of the Gregorian calendar.Closely related is the custom of dual dating, where writers gave two consecutive years to reflect differences in the starting date of the year, or to include both the Julian and Gregorian dates.The need for change arose from the realisation that the correct figure for number of days in a year is not 365.25 (365 days 6 hours) as supposed by the Julian calendar but almost exactly 365.2425 days (365 days 5 hours 49 minutes 12 seconds), a reduction of 10 minutes 48 seconds per year: the Julian calendar has too many leap years. When this usage is encountered, the reader should not assume that the British adoption date is intended, or that the 'start of year' change and the calendar system change were adopted concurrently, or even that religious adoption accompanied civil adoption.The consequence was that the basis for calculation of the date of Easter as decided in the fourth century had drifted from reality. In the case of Eastern Europe, for example, all of these assumptions would be incorrect.In Alaska, the change took place after the United States purchased Alaska from Russia.Friday, 6 October 1867 was followed by Friday, 18 October.Events in continental western Europe are usually reported in English language histories as happening under the Gregorian calendar.For example, the Battle of Blenheim is always given as 13 August 1704.