Julian calendar irregular years, this extra-long year was, and is, referred to as the "last year of confusion". The new calendar began operation after the realignment had been completed, in 45 BC. The Julian months were formed by adding ten days to a regular pre-Julian Roman year of 355 days, creating a regular Julian year of 365 days. Two extra days were added to January, Sextilis (August) and December, and one extra day was added to April, June, September and November. February was not changed in ordinary years, and so continued to be the traditional 28 days. Thus, the ordinary (i.e., non-leap
Bissextus ecclesiastical calendars, the intercalary day is added for convenience at the end of the month of February, as February 29, and years in which February has twenty-nine days are called "bissextile," or leap years. Bissextus Bissext, or bissextus (Lat. "bis", twice; "sextus", sixth) is the day which is added to the Gregorian calendar every fourth year (except those evenly divisible by 100, unless they are divisible by 400) to compensate for the six-hour difference in length between the common 365-day year and the actual length of the solar year. Originally, the day was inserted after the 24th of February, i.e.