Later Zoroastrian and Perso-Islamic literary tradition, including the epic Shahnameh, places the Bactrian region around Balkh at the center of Zoroaster's own life and teaching, in some tellings identifying Balkh directly as the place where he first proclaimed his message to a receptive king, and in others as the site of his death. Those accounts, composed many centuries after Zoroaster is thought to have lived, gave Balkh a religious prestige it retained long after Zoroastrianism itself had been displaced as the region's dominant faith, reflected in the honorific Umm al-Bilad, Mother of Cities, that later Arabic sources applied to it in recognition of both its antiquity and its legendary religious weight.
Modern scholarship treats these accounts with considerable caution. The historical Zoroaster's dates, homeland and even century of activity remain genuinely disputed among specialists, with proposed locations ranging across a wide swath of Central Asia and Iran, and no contemporary evidence independently confirms Balkh specifically as opposed to crediting it as one strand within a body of later tradition that developed over many centuries after any historical events it claims to describe. Balkh's Zoroastrian reputation is, in that sense, a genuinely significant fact about the region's religious memory whether or not it is also a fact about Zoroaster's own life.