The Julian calendar was in place then. It preceded the Gregorian calendar that we now use. Like the Gregorian calendar, the Julian calendar had 365 days, with a leap year of 366 days. There is only a slight difference of a few minutes between the precise length of the Julian calendar and the Gregorian calendar.
<<>> The Julian calendar has a leap year every 4 years, with an average year of 365.25 days. The Gregorian calendar we use now has 97 leap years in every 400 years, so the average year is 365.2425 days.