Moreover, under piaculum are confused purification, propitiations and expiations; Smith's contention that purifications, whose magical character he recognizes but interprets as late, are not sacrificial, is far from conclusive.
In fact, the Persian religion throughout all its multitude of purifications, observances and expiations was a constant warfare against impurity, death and the devil.
They are to all appearance the work of a school of priests, who, after the destruction of the Temple in 586 B.C., began to write down and codify the ceremonial regulations of the pre-exilic times, combining them with an historical narrative extending from the Creation to the establishment of Israel in Canaan; and who completed their work during the century following the restoration in 537 B.C. The chief object of these sections is to describe in detail the leading institutions of the theocracy (Tabernacle, sacrifices, purifications, &c.), and to refer them to their traditional origin in the Mosaic age.
As to the manual rites of the daily cult, all that can here be said is that incense, purifications and anointings with various Oils played a large part; the sacrifices consisted chiefly of slaughtered oxen and geese; burnt offerings were a very late innovation.
A collection of oracles, a theogony, an epic poem on the Argonautic expedition, prose works on purifications and sacrifices, and a cosmogony, were attributed to him.