European dating system
Although current historical scholarship calls for retention of Old Style dates in transcriptions, historians and genealogists need to be aware that some people living at the time converted the date of an event, such as a birthday, from Old Style to New Style.
George Washington, for example, was born on February 11, 1731 under the Julian Calendar, but afterwards recognized the date February 22, 1732 to reflect the Gregorian Calendar.
Because the year began in March, records referring to the "first month" pertain to March; to the second month pertain to April, etc., so that "the 19th of the 12th month" would be February 19.
When first implemented, the "Julian Calendar" also moved the beginning of the year from March 1 to January 1.
However, following the fall of the Roman Empire in the fifth century, the new year was gradually realigned to coincide with Christian festivals until by the seventh century, Christmas Day marked the beginning of the new year in many countries.
By that time, the discrepancy between a solar year and the Julian Calendar had grown by an additional day, so that the calendar used in England and its colonies was 11 days out-of-sync with the Gregorian Calendar in use in most other parts of Europe.
England's calendar change included three major components.
In general, double dating was more common in civil than church and ecclesiastical records.