The calendar It is an object that is part of our daily life and we are quick to reperirne a copy near the end of the year (After the summer we will have to look for the new Calendar 2020).

It is difficult to think how his story is long and complex: ripercorriamone in short key stages.

Ancient Rome

calendarThe first schedule of’Ancient Rome It dates back to its legendary founder, Romulus.

The information about him are quite nebulous and, sometimes, contradictory.

According to what stated by Ovid, the months of the year were only 10 and they began from March, but according to some historians they existed January and February.

Livy informs us in some detail the calendar of Numa Pompilius, second king of Rome.

It was a lunisolar calendar 12 months consist of days ranging from 29 a 31.

Throughout the year consisted 355 days and, to retrieve the ten days of the calendar year, every two years, he was part of a month, Mercedonio or Intercalare, lasting 22 O 23 days.

This calendar, even though over time it underwent several changes, It remained in force until 46 a.C.

The Julian calendar

The calendar of Numa, It used throughout the Republican era, poorly managed by the priests that they occupied, He ended up accumulating a delay of about three months compared to the natural succession of the seasons, enough to postpone the summer in October and November that, instead, They were autumn months.

To the situation would remedy Julius Caesar with the introduction of a new calendar, say giuliano in his honor.

The intention was to create a more functional compared to the previous calendar.

Sosigene, eminent Alexandrian astronomer, gained important assignment.

The 46 (O 45) a.C., year in which it entered into force, It was very special: They inserted two months extra between November and December to make back the months and the seasons corresponded traditional, besides another intercalation of Mercedonio.

Almost certainly that year lasted 445 days.

For the rest Sosigenes settled 365 days per year plus a leap year every 4.

The Gregorian calendar


Papa Leone XIII

The Gregorian calendar, currently it used in most countries in the world apart from a few exceptions, It was officially introduced 4 October 1582.

In fact, the 1582 hard 10 days less than normal.

The decision was made and enforced by Papa Gregorio XIII, with the intent to overcome the phase shift occurred as created with the Julian calendar.

Practically, He was late with the calendar year and you had to make up this gap.

After a job that lasted 4 years and chaired by doctor Aloysius Lilius and astronomer Cristoforo Clavio, the papal bull among the most serious, He gave the start to the Gregorian calendar.

It was equal to that Julian, but there were multiple deleted leap of centennial year 400.

So what was recovered scrap 5 ore, 48 minutes and 46 seconds “forgotten” For centuries, with the result of the next phase shift.

E’, let's say so, funny, think that day from 5 al 14 October's 1582 They were regarded as non-existent by Gregory XIII: people on the evening of 4 October of that year they went to bed, the next morning they woke the 15 October.