Before1752 most official records in England used the Julian calendar in which the first day of the year was the 25th of March, so called "Ladies Day". The Gregorian calendar, in which the year starts on the 1st of January, was first introduced by the Pope Gregorius in 1682 in most Roman Catholic countries on the continent. It was only later adopted by the Protestant countries. In England the Gregorian calendar came into official use in 1752, although it was gradually being adopted by many officials from 1700 onwards and by 1722 was in general use in most official records.
As a result, dates that fall between 1st January and 24th March before circa 1700 are 1 year less less than we would normally consider them to be. For example, someone born on 10th February 1711 would have had their birth date recorded as 10th Feb 1710 in official records because the year 1710 didn't end until 25th March, on Ladies Day.
On our website, to prevent misunderstanding of the year, we follow the convention of indicating the year as 1735/6 to indicate 1735 according to the Julian calendar and 1736 according to the Gregorian calendar. For dates before 1700 we quote the Julian year to remain true to original records.