Farsi in one of the branches of the west-south group of Iranian Languages. Todays Iranian Languages and Dialects are the descendent of Proto-Iranian Language which was closely related to Proto-Indo-Aryan Language. Their antecedent was Proto-Indo-Iranian Language which is itself a branch of the Proto-Indo-European Language. ‘Farsi’, ‘Dari’, and ‘Tajiki’ are the varieties of Persian Language in Iran, Afghanistan, and Tajikistan.
Every language has three historic periods: Old, Middle, New. Old Persian (O.P) was prevalent from 1000-331 B.C; the Achaemenidian Inscriptions are the most important documents from this language. Middle Persian spun from 331 B.C to 8/9 A.D, and the most common information from this language is from the Sasanid Dynasty. New Persian languages have been in use from 8/9 A.D to this day and they have extended over a large geographical are: from Syria, Turkey and Iraq in west, Central Asia and Caucasus in North, Pakistan and China in East, and some areas in the countries beside Persian Gulf and islands of Strait of Hormuz in South.

The names of months in the Persian solar calendar originate from Zoroastrian history and the Persian Empire which dates back to 2500 years ago. After the introduction of Islam, the calendar was adjusted to begin with the date of the prophet Mohammed’s migration from Mecca to Medina in 622 AD.
According to this calendar, a solar year has 12 months lasting 30 days each (366 every leap year).