The Gregorian Calendar completes today (October 4) 436 years and Google has prepared a homage in the form of Google Doodle. This calendar, which is commonly used almost everywhere in the world, marks the days and months of the solar year. (on October 4, 2018) (only began to be counted from the 15th, because they still messed up in the days, they skipped 11 days in the count to close on PASCAL day).
This count was created by the Catholic Church and by Pope Gregory XIII in October 1582, and only began to be used, in fact, on the 15th of that same month.
As a convention and for convenience, the Gregorian calendar is adopted to mark the calendar year around the world, facilitating the relationship between nations. This unification stems from the fact that Europe has historically exported its standards to the rest of the globe.
The Gregorian calendar presents some defects, both from an astronomical point of view and in its practical aspect. For example, the number of days of each month is irregular (28 to 31 days); moreover, the week, adopted almost universally as a labor unit of time, is not integrated in the months and is often spread over two different months, harming the rational distribution of labor and wages.
Another problem is the mobility of the Easter date, which runs from March 22 to April 25, disrupting the length of school quarters and numerous other economic and social activities.
The shift to the Gregorian calendar took place over more than three centuries. Firstly it was adopted by Portugal, Spain, Italy and Poland; and successively, by most European Catholic countries. The countries where Lutheranism and Anglicanism predominated would take time, in the case of Germany (Bavaria, Prussia and other provinces) (1700) and Great Britain (England and Wales) (1752). The adoption of this calendar by Sweden was so problematic that it even generated the 30th of February. China approved it in 1912, Bulgaria in 1916, Russia in 1918, Romania in 1919, Greece in 1923, and Turkey in 1926.
Some people keep other calendars for religious use even with chronology different from that adopted by the Roman Catholic Church. As proposed by Dionysius Exiguus (470 - 544) Romanian monk the starting point of Christian chronology dates as the year of Christ's birth.
According to the Gregorian calendar, today is December 31, 2018. For this same date other calendars point different years, as: Ab urbe condita 2771; Babylonian Calendar 6768; Bahá'í Calendar 174-175; Buddhist Calendar 2562; Hebrew Calendar 5778-5779; Hindu Calendar Vikram Samvat 2074-2075; Hindu Calendar Shaka Samvat 1940-1941; Hindu Calendar Kali Yuga 5119-5120; Holocene Calendar 12018; Iranian calendar 1396-1397; Islamic Calendar 1439-1440 among others.
