"Ahura Mazda spoke to Spitama Zarathushtra, saying: ‘I have made every land dear (to its people), even though it had no charms whatever in it: had I not made every land dear (to its people), even though it had no charms whatever in it, then the whole living world would have invaded the Aryan Expanse’."
This Avestan text is the first to mention the lands created by Ahura Mazda for the Iranian people. These include Sogdiana, Bactria and Chorasmia, areas that today from part of the Central Asian steppes. The Sogdians were the dominant traders of what became known as the Silk Road established during the Parthian period (247 BCE - 224 CE) and their capital, Afrasiyab (modern Samarkand), was a major crossroads for trade.
Archaeological finds in Sogdian cities have revealed murals depicting scenes with distinctly Zoroastrian elements such as priests wearing the mouth covering, padam, to prevent polluting fire with their breath, and the use of clay ossuaries to take the bones of the dead after exposure. Ritual implements used in the main priestly act of worship, the yasna, are among new finds in the Dzhartepe temple near Samarkand. Sogdians also established trade with China where a number of fire temples were built during the early Tang dynasty (circa 630 CE). A remarkable find has been a manuscript fragment from Dunhuang on the Silk Road, in China, which contains the oldest surviving fragment of Zoroastrian scripture in the form of one of the most holy of prayers, the Ashem Vohu.