The word is also the proper name of the divinity Asha, the Amesha Spenta that is the hypostasis or "genius" of "Truth" or "Righteousness". In the Younger Avesta, this figure is more commonly referred to as Asha Vahishta ("Aṣ̌a Vahišta", "Arta Vahišta"), "Best Truth". The Middle Persian descendant is "Ashawahist" or "Ardwahisht"; New Persian "Ardibehesht" or "Ordibehesht". In the Gathas— the oldest texts of Zoroastrianism, thought to have been composed by Zoroaster —it is seldom possible to distinguish between moral principle and the divinity. Later texts consistently use the 'Best' epithet when speaking of the Amesha Spenta, only once in the Gathas is 'best' an adjective of "aṣ̌a/arta".