This makes me feel so disconnected from the universe.

"They reckoned from three points in the month: the Calends, Nones, and Ides.
The Calends were always the first of the month, the Nones and Ides were the fifth and thirteenth, except in May, July, March, and October, (May Julius march over? ) when they came two days later, on the seventh and fifteenth respectively.
From these points dates were reckoned backward, so that everything after
the Calends was so many days before the Nones, and everything after the
Ides was so many days before the Calends of the next month; for instance,
the 28th of June was the fourth day (the Romans counted the
days at each end of the series !) before the 1st of July."

"The earliest Roman calendar had a year of ten months, of which March
was the first. This arrangement led to difficulties, which the Romans tried
to adjust in various ways. Finally the best solution seemed to be to add
two more months, January and February were inserted at the beginning of
the year. But still the calendar year failed to agree with the solar year,
so that by the time of Julius Caesar the calendar was a whole season (three
months) out of the way. In 46 B.C. Caesar established the calendar
much as we have it today, except that February had twenty-nine days. He
changed Quintilis, the fifth month, to Julius. His successor, Augustus,
changed Sextilis, the sixth month, to Augustus, adding to it one day from
February, so that his month might be as long as the one in honor of Julius. "

From my old 1933 Smith and Thompson "First Year Latin" Reader.