Dastur

A dastur holds the most senior rank of the Zoroastrian priesthood, historically presiding over a fire temple district or a major fire temple itself, particularly an Atash Behram, the highest of the three grades of consecrated fire in Zoroastrian practice, whose establishment and ongoing ritual maintenance require the participation of numerous priests over an extended, elaborate consecration process. Zoroastrian fire temples are graded according to the complexity of the fire's original consecration and the resulting purity and sanctity attributed to it, the Atash Behram standing above the Atash Adaran and Atash Dadgah, and a dastur's authority and prestige is closely tied to association with the more senior grades of temple and fire.

The office and the wider Zoroastrian priesthood are today divided between the two main branches of the faith, the Parsi community centered in India, chiefly Mumbai and Gujarat, descended from Zoroastrians who emigrated from Persia beginning around the tenth century CE, and the smaller Irani Zoroastrian community that remained in and later re-emigrated from Iran, each maintaining its own priestly lineages and, in some liturgical and calendrical details, distinct practices, reflecting centuries of separate historical development between the two branches.

Zoroastrian priesthood is traditionally hereditary, restricted to men born into specific priestly families, a lineage-based qualification requiring extensive training from a young age in the Avestan liturgical language and the detailed procedures of Zoroastrian ritual, a demanding formation historically undertaken within the priestly community itself rather than open to conversion or entry from outside the hereditary priestly lines. Becoming a dastur specifically requires advancement through preliminary priestly grades and recognized standing among the wider priesthood, typically associated with service at a particularly significant fire temple or community.

The Zoroastrian community worldwide has declined substantially in absolute numbers over the twentieth and twenty-first centuries, a demographic trend that has placed real strain on the hereditary priesthood specifically, since a shrinking population of eligible priestly families produces fewer candidates willing or able to undertake the lengthy traditional training when the alternative of pursuing secular education and careers offers considerably different prospects; several Zoroastrian communities and religious bodies have discussed, with varying degrees of openness and continuing debate, whether and how the tradition's hereditary priestly requirement might need to adapt to sustain an adequately trained priesthood for future generations.