bissextile

There is no doubt that the bissextile day eventually became the earlier of the two days for most purposes.

Mart.; hence it is called in English the bissextile day.

There is debate about the exact position of the bissextile day in the early Julian calendar.

The effect of the bissextile day on the nundinal cycle is not discussed in the sources.

In some places the tradition was tightened to restricting female proposals to the modern leap day, February 29, or to the medieval (bissextile) leap day, February 24.

This section always places the intercalary day on 29 February even though it was always obtained by doubling 24 February (the bissextum (twice sixth) or bissextile day) until the late Middle Ages.

The Alexandrian calendar adapted the Egyptian calendar by adding a 6th epagomenal day as the last day of the year in every fourth year, falling on the 29 August preceding a bissextile day.

In 1645 he essayed a reformation of the calendar; but although his plan of omitting the bissextile day (29 February) for the next 40 years was approved by the king, the matter was dropped owing to the turbulent times.

All later writers, including Macrobius about 430, Bede in 725, and other medieval computists (calculators of Easter), continued to state that the bissextum (bissextile day) occurred before the last five days of February.

Hence, it is necessary to suppress the bissextile day at the end of every century which is not divisible by 400, while it is retained at the end of those which are divisible by 400.

A leap year (or intercalary or bissextile year) is a year containing one additional day (or, in the case of lunisolar calendars, a month) in order to keep the calendar year synchronized with the astronomical or seasonal year.