Gregorian Calendar

The Gregorian Calendar is the most popular calendar used nearly around the world. The Gregorian Calendar is a modification of the discontinued Julian Calendar. It is named after the pope Gregory XIII, whom he introduced in October 1582. 
== Development and Modification ==
See More at: Dionysius Exiguus
 Dionysius Exiguus (c. 475 - c. 550) was the creator of the Gregorian Calendar. He was assigned by the church to calculate the exact date for Easter. Dionysius favored of measuring the calendar based on the incarnation (A mistake suggests he was measuring from birth, which is not the same as incarnation) of Jesus Christ.
"I have been unwilling to connect our cycle with the name of an impious persecutor, but have chosen rather to note the years from the incarnation of Jesus Christ, to end the commencement of our hope might be better known to us and that the cause of man's restoration, namely, our Redeemer's passion, might appear with clearer evidence." - Dionysius Exiguus
The impious persecutor was the Emperor Diocletian, under whose rule of Rome many Christians had been martyred. Dionysius wanted to start his own table, he did not want to merge it with the murderer of Christians (Diocletian) 
=== Construction of Table ===