[jsrjenkins]

Actually the Romans counted their months beginning with March:

March (1) April (2) May (3) ... July (5) (named after Julius Caesar) August (6) (named after Augustus) September (7) ... etc.

The reason being in the ancient world all serious activity begins in the spring, especially war campaigns which were to be under the aegis of the god Mars, from which the name of the month.

Note that when we have a leap year we add the extra day to the end of the Roman year, that is at the end of February which is the last month of the year.

More precisely, we duplicate the sixth of the calends of March. This is why in French the leap year is called 'bisextile'.