出典:Wiktionary
To avoid interfering with Rome's religious festivals during his 46 bc calendar reform, Julius Caesar added no permanent days to the Roman month of February and placed his system's leap day well before the end of the month,[1] following the festival of Terminalia. Initially, no day was added at all. Instead, the fifth day before the 1st of March—reckoned inclusively by the Romans as the "sixth calends of March"—was considered to last for 48 hours instead of 24 and the year was accordingly known as a "bissextile year". Roman inclusive counting initially caused the priests to add leap days every three years instead of four, and Augustus omitted bissextile years for a few decades until the count became accurate again. The doubled day of the Julian calendar was eventually understood as two separate days, but the leap day was taken to be the first 24-hour period (Feb. 24) rather than the second (Feb. 25). In Britain and the United States, no authority has ever altered this day as the extra one added to the year, although Sweden and Finland have both formally enacted legislation to change it to February 29.[2] Regardless, February 29 is popularly considered the "leap day" of leap years[3] and has been since the late medieval introduction of sequential reckoning of the days of months.
the sailing day
the declining day
夕暮れ.
a nap
a nap
the livelong day