How many months existed before Caesar changed the Roman calendar?

There where 10 months (304 days) in the Roman calendar before Caesar changed it. It was not used for long because it didn't align with the seasons. The 10 months were: Martius (March), Aprilis (April), Maius (May), Junius (June), Quintillis (July), Sextilis (August), September, October, November and December.
There was no January or February on the calendar. March was the first month on the calendar.