Proleptic

Proleptically means in the era ( chronology ), time that a system relies on its defined zero point out in the past. The adjective proleptically comes from Greek προληπτικός and means " forward leaving ", " forward -looking".

Standard time measurement system of astronomy as well as the chronology is the Julian date, one - despite the date 0.0 on January 1, -4712 ( 4713 BC) 12:00 - not proleptisches Dezimalzeitsystem that in the problems of dating proleptic the form of a uniform continuous time scale bridged.

Proleptic calendar

A calendar system has a certain reference date, the epoch at which the year count starts. All data prior to that date specified in this calendar system, then hot proleptically dated. You have negative year numbers or be described with " BCE " and similar terms.

Actually calendars are basically proleptically. That is, at the time of its introduction all historical data will be recalculated according to the new rules and from then specified in the new calendar system in general.

Not proleptic calendar

The Gregorian calendar is expressly proleptically, with the result that there is still a " piecemeal " calendar. Julian until the 4th of October 1582 Gregorian since October 15, 1582 The ten calendar days between them have, at least in Rome, Italy, Spain and Portugal historically never existed. In other countries - depending on the launch date - there were 10 to 13 different calendar days that never existed.

Another classic problem dating is about the so-called kinky 708 a and c. , In which the Roman to the Julian calendar was changed, and his unsecured his term proleptic backdating.

Furthermore, not all used proleptic calendar systems based on a system of eras ( era ) are constructed, especially all dynastic calendar systems. The annual counting begins at each epoch ( beginning of an era ) new, but previous data are given in terms of the respective valid at that time period. Examples: Egyptian calendar, chinese calendar, Japanese calendar with Nengo, Mayan calendar.

The French Revolutionary calendar was also not proleptically. He stepped on 4 Frimaire II (24 November 1793) in force - backdated to 1 Vendémiaire I (September 22, 1792 Date of equinox after the proclamation of the First French Republic the day before). Continue to date the Gregorian calendar was used for the period prior to this date of origin.

On the problem of dating

The conversion of historical time and calendar systems in Julian date is a built on a depending on the system more or less complicated formula set that is constructed based on historical ascertainable facts: Historic datings ( details of the date and time of day) are, because until the late 20th century has been no global binding, currently available reference about simultaneity, only traditional assignments that must be matched on the basis of source location with other contemporary events. Typical key data are as astronomical events (such as eclipses ), which can be dated based on today's sufficiently precise computational models ( astronomical chronology ) and provide the basis of the conversion Gregorian - proleptischer data to the present time scale give.