Proleptic Gregorian calendar Proleptic Gregorian calendar The proleptic Gregorian calendar is produced by extending the Gregorian calendar backward to dates preceding its official introduction in 1582. In countries that adopted the Gregorian calendar later, dates occurring in the interim (between 1582 and the local adoption) are sometimes "Gregorianized" as well. For example, George Washington was born on February 11, 1731 (Old Style), as Great Britain and its possessions were using the Julian calendar with English years starting on March 25 until September 1752. After the switch, that day became February 22, 1732, which is the date commonly given as Washington's birthday. The proleptic
Ramadan (calendar month) religious observances consists of fasting and extra prayers. Some important historical events during this month are generally believed to include: Laylat al-Qadr is observed during one of the last ten days of the month (typically the odd nights). Muslims believe that this night which is also known as "The Night of Power" is better than a thousand months. This is often interpreted as praying throughout this night is rewarded equally with praying for a thousand months (just over 83 years i.e., a lifetime). Many Muslims spend the entire night in prayer. In Islamic eschatology: Ramadan (calendar month) Ramadan (Arabic: )