Nowruz is partly rooted in the tradition of Iranian religions, such as Mithraism and Zoroastrianism. In Mithraism, festivals had a deep linkage with the Sun’s light. The persian festivals such as Mehregan (autumnal equinox), Tirgan, and the eve of Chelle ye Zemestan (winter solstice) also had an origin in the Sun god (Mithra). Among other ideas, Zoroastrianism is the first monotheistic religion that emphasizes broad concepts such as the corresponding work of good and evil in the world, and the connection of humans to nature.