Zoroastrianism is an Indo-Iranian religion, based on the teachings of the prophet Zarathustra, or Zoroaster.
Almut Hintze (Zartoshty Brothers Professor of Zoroastrianism at the School of Oriental and African Studies, University of London) writes that, “The roots of the Zoroastrians reach back to prehistoric Central Asia in the 2nd millennium BCE. According to their own tradition, the… religion was inaugurated by Zarathustra. Later the Greeks turned his Iranian name into Zoroastrēs, from which the name Zoroastrian derives, denoting a follower of the religion of Zoroaster. Zoroastrianism flourished for over a thousand years as the state religion of the three great Iranian Empires: the Achaemenids, the Parthians and the Sasanians, but was ousted by Islam following the Arab conquest of Iran in 651 CE.” 
Otago Museum has a single item in its collection associated with Zoroastrianism: a small embroidered textile fragment (image above). Researcher, Margery Blackman, identified it on the basis of the imagery and embroidery techniques, and suggests that the maker was a young woman from a Zoroastrian community – probably from the Iranian cities of Yazd, or Kerman, or a nearby village. It is from a garment made for her bridal costume, and possibly dates from the late 19th century.
The embroidery is worked in 2-ply silk thread in stem and two colour chain stitches. It features “two sun discs with fourteen points and facial features, two four-legged animals with curled tails, three flowering plants in oval containers, and two leafy plants with a small bird perched on top and a fish swimming at their base... A black and white silk cord is stitched to one side …where a seam joined this piece to another panel of fabric”. 
“It could have been part of a tunic (qamis), or from the pantaloons (shalvar) worn underneath. These voluminous trousers were made from a number of differently coloured embroidered panels joined to a waist-hip section of plain blue cotton. The shalvar was gathered at the waist and ankle. Only the colourful lower part was visible with the qamis reaching well below the knees. Some panels of the qamis were embroidered, some were left plain and others made from printed fabrics.” 
Describing a pair of these distinctive trousers in their collection, the Victoria and Albert Museum catalogue notes, “Like other religious minorities in Iran, Zoroastrians were required to dress to identify their religion. They wore brightly coloured clothing and did not usually veil their faces. This created an obvious contrast with the outdoor clothing worn by Muslim women. A Zoroastrian woman would typically wear a tunic (qamis), together with loose trousers (shalvar) gathered at the ankle. These trousers were made from textile remnants because there were restrictions on Zoroastrians buying full widths of fabric. Women covered their heads with a small fitted cap (lachak), over which they would wrap several shawls around their head and shoulders.” 
Image: Pair of embroidered Zoroastrian woman's trousers, early 20th century. Weltmuseum Wien, Austria 
Although there is still a Zoroastrian community in Iran, many followers migrated to India where they became known as Parsis (as they came from Persia). Professor Hintze estimates there are currently about 130 000 Zoroastrians world-wide.
 Margery Blackman and Moira White. 2015. 'Identifying an embroidered silk fragment', Context 31: 40-42