Inter gravissimas

With the bull Inter gravissimas from February 24, 1582, decreed by Pope Gregory XIII. named after him Gregorian calendar. Like all papal bulls is also this according to its Latin opening words ( incipit ) quotes denominated translated here: " The most important ( tasks of our pastoral office ... ) ". They point out that the Council of Trent had left, among other things, the reform of the Breviary the Pope. This included not only completed items the annual determination of the Easter date and the page associated with Easter Holidays ( Ash Wednesday to octave of Pentecost ), where the date of Easter should be calculated on the basis of astronomical.

The problem

For the calculation of Easter three things must be fixed: the exact date of beginning of spring, the determination of the full moon in spring and finally the determination of the following Sunday is to celebrate the Easter then. The liturgical beginning of spring was the Council of Nicaea - then correctly - set to March 21. Due to the inaccuracy of the Julian calendar but the astronomical vernal equinox occurred since an early ten days.

Preparation

The calendar reform had already been taken by various popes in attack, previously discussed approaches had but either can not provide lasting solutions or have not been compatible with the old church use. The method developed by Aloysius Lilius, and now by his brother Anthony the Pope brought to the attention working with a new cycle of epacts who consider the true solar year and could apply for all times. The Pope had sent this model the most important princes of Christendom and to the great universities, which have responded favorably. With the finalization Gregor experts had commissioned from different countries who had the Lilius'sche model basis and still slightly restored.

Arrangement

The bull decreed that ten few days have (including 5 to 14 October 1582) to be omitted and that the day of the follow on the 4th of October, when October 15, 1582 should be counted. On this and the following days, but also several saints' feasts are nachzufeiern, after October 17 everything back as before. In this way, will fall back on the 21st of March in 1583 the spring equinox.

In order to keep the calendar stable, put the bull finds that, as before, every four years a leap year should be maintained, even in 1600, but then each of the following four secular years, only the last ( 1700, 1800 and 1900 not for 2000 again, and so on).

The actual determination of the date of Easter should not be directed more by the Golden Number, but according to the newly introduced, based on the golden number of cycle epacts from 1583. Since the sequence of weekdays was maintained on the Thursday, October 4, following October 15 fell on a Friday, not a Monday. And, along with that of the dominical letter G changed to C.

Pressure

The new calendar should be printed with the adjusted martyrology in Rome and published and come into force from 15 October 1582. To ensure the correctness of the text arrangement initially received Antonius Lilius ( text omitted) a filled with the usual sanctions pressure privilege. Foreign printer should meet to papal license. Since Lilius but could not meet the demand, him the sole right to exploit, however, was withdrawn in the Papal States.

Dissemination

The cop committed under threat of ordinary penalties all sacred ministers and all Christians to use the new calendar from the ten days to be omitted. Emperor Rudolf II, the other kings, princes and cities have been asked and commissioned to introduce the calendar in their subjects to maintain Christian unity.

Detailed provisions

Deadlines for monthly or annual payments that would be affected by the omission of ten days should be extended by ten days in the case of a legal dispute.

Introduction

The Gregorian calendar was immediately introduced in Catholic countries in Protestant and Orthodox countries only gradually.