Armenian calendar

The Armenian calendar was the main calendar used in Armenia during the medieval period. The year in this calendar is exactly 365 days long, divided into twelve months of thirty days each, plus five extra days that are called "aveleacʿ" in the Armenian language, which are not a part of any month. The first year in the Armenian calendar is equal to the year 552 AD in the Gregorian calendar. This calendar was mainly used in the medieval era, but is also used in modern times by some Armenian nationalists.
This calendar has no leap days. For that reason, it shifts backwards against the Gregorian calendar over a period of 1,461 years.
Months.
The twelve months in the calendar have differen names to the months usually used in English.