from
The Collaborative International Dictionary of English v.0.48
Roman calendar \Roman calendar\
The calendar of the ancient Romans, from which our modern
calendars are derived. It is said to have consisted
originally of ten months, Martius, Aprilis, Maius, Junius,
Quintilis, Sextilis, September, October, November, and
December, having a total of 304 days. Numa added two months,
Januarius at the beginning of the year, and Februarius at the
end, making in all 355 days. He also ordered an intercalary
month, Mercedinus, to be inserted every second year. Later
the order of the months was changed so that January should
come before February. Through abuse of power by the pontiffs
to whose care it was committed, this calendar fell into
confusion. It was replaced by the Julian calendar. In
designating the days of the month, the Romans reckoned
backward from three fixed points, the calends, the nones, and
the ides. The calends were always the first day of the month.
The ides fell on the 15th in March, May, July (Quintilis),
and October, and on the 13th in other months. The nones came
on the eighth day (the ninth, counting the ides) before the
ides. Thus, Jan. 13 was called the ides of January, Jan. 12,
the day before the ides, and Jan. 11, the third day before
the ides (since the ides count as one), while Jan. 14 was the
19th day before the calends of February.
[Webster 1913 Suppl.]