Proleptic Gregorian calendar Julian and proleptic Gregorian calendar dates are as follows: The table below assumes a Julian leap day of 29 February, but the Julian leap day (the bissextile day) was in Latin or 24 February (see Julian reform), so dates between 24 and 29 February in all leap years were irregular. Note: When converting a date in a year which is leap in one calendar but not the other, include 29 February in the calculation when the conversion crosses the border between February and March. Proleptic Gregorian calendar The proleptic Gregorian calendar is produced by extending the Gregorian calendar backward to
Berber calendar of Mauretania Caesariensis and the Roman province of Africa, as it is a surviving form of the Julian calendar. The latter calendar was used in Europe before the adoption of the Gregorian calendar, with month names derived from Latin. Berber populations previously used various indigenous calendars, such as that of the Guanche autochthones of the Canary Islands. However, relatively little is known of these ancient calendrical systems. The agricultural Berber calendar still in use is almost certainly derived from the Julian calendar, introduced in the Roman province of Africa at the time of Roman domination. The names of the months