The data on which Bulliet's study was based limited the validity of this paradigm to generalizations about full, formal conversions in an urban environment. The situation in rural areas and individual regions may have been quite different, but the overall pattern is consistent with what can be deduced from traditional historical sources. Although in some areas, for example, Shiraz at the time of Moqaddasi's visit in about 375/985 (p. 429), there may still have been strong non-Muslim elements, it is reasonable to suppose that the Persian milieu as a whole became predominantly Islamic within the period of time suggested by Bulliet's research.[12]