"When the Pope Gregory revised the calendar in 1582, a certain number of days were omitted from the calendar at a particular time, resulting in two separate styles of dating. England persisted in using the "Old Style" until 1752, because of religious differences. The Old Style also often dated the beginning of the year from March 25 rather than January 1, and this area of the site takes this difference into account. Thus March 8, 1735, Old Style is really March 19, 1736 in the New Style! Occasionally, particularly in dating material between 1582 and 1755 or so, it becomes necessary to convert back and forth."