There are specific references to the celebration of Nowruz during the reign of Vologases I (51–78 CE), but these include no details. Before Sassanids established their power in Western Asia around 300 CE, Parthians celebrated Nowruz in autumn, and the first of Farvardin began at the autumn equinox. During the reign of the Parthian dynasty, the spring festival was Mehregan, a Zoroastrian and Iranian festival celebrated in honor of Mithra.