THE GREGORIAN CALENDAR.
The Julian calendar was framed about 46 years before Christ. Cæsar made the year consist of 365 days; and the annual excess of six hours, which amounted to one day in four years, was taken into account by making every fourth year (leap-year) consist of 366 days. But Cæsar’s correction of the calendar was imperfect, being founded on the supposition that the solar year consisted of 365 days, 6 hours, whereas the true solar year consists of 365 days, 5 hours, 48 minutes, 45½ seconds. Thus the Julian year exceeded the solar 11 minutes 14½ seconds,—which amounted to a whole day in 130 years. In consequence of this inaccuracy, the vernal equinox, which happened on the 25th of March in the time of Julius Cæsar, had receded to the 21st of March in the year 325, and was fixed to that day by the Council of Nice. Attempts were afterwards made to effect some change in the calendar; but a complete reformation was not made until 1582. Pope Gregory XIII. invited to Rome the most learned astronomers of the age; and, after the subject had been discussed ten years, it was decreed that the vernal equinox, which had receded ten days since the Council of Nice, and consequently happened on the 11th of March, should be brought back to the 21st of March, and that for this purpose ten days should be taken from the month of October, 1582. To avoid future deviation, it was determined that instead of every 100th year being leap-year, every 400th year only should be leap-year. By this plan—a diminution of three days in 400 years—the error in the present calendar will not exceed a day and a half in five thousand years.
The calendar thus reformed by Pope Gregory was immediately introduced into Catholic countries, but was not finally adopted in Great Britain until 1752, when, by act of Parliament, eleven days were struck out of the calendar, the 3d of September being reckoned the 14th. The Greek Church still obstinately adheres to the old style.