In the "Aban Yasht" ("Yasht" 5), which is nominally dedicated to the waters, veneration is directed specifically at "Aredvi Sura Anahita", another divinity identified with the waters, but originally representing the "world river" that encircled the earth (see "In tradition", below). The merger of the two concepts "probably" came about due to prominence given to Aredvi Sura during the reign of Artaxerxes II ("r." 404-358 BCE) and subsequent Achaemenid emperors. Although (according to Lommel and Boyce) Aredvi is of Indo-Iranian origin and cognate with Vedic Saraswati, during the 5th century BCE Aredvi was conflated with a Semitic divinity with similar attributes, from whom she then inherited additional properties.