Head of all priests had special rights and privileges.
Reprinted from The Jewish Religion: A Companion, published by Oxford University Press.
High Priest was the chief among the priests who officiated in the Temple. The Hebrew is kohen gadol. The High Priest was distinguished from ordinary priests in a number of respects.
Based on Exodus 28, the Talmudic sources state that every priest, while performing the Temple service, had to wear four garments: a tunic, a girdle, a turban, and breeches reaching from the hips to the thighs. These four were worn by the High Priest as well but in addition he wore four further garments. These were: the ephod, a kind of apron, worn from behind with a sash in front around his middle; the meil, a coat reaching from his neck to his feet with bells and pomegranate-shaped adornments at its hem; the hoshen, a breastplate to which were affixed twelve precious stones containing the engraved names of the 12 tribes; and the tzitz, a gold forehead piece on which was engraved the words: "Holy to the Lord."
The breastplate is said in the Exodus account to contain the Urim Ve-Thummim, an oracle. Whatever the original meaning of the Urim Ve-Thummim, in the Talmudic tradition it was not a separate object but represented the miraculous illumination of certain letters of the stones on the breastplate so as to yield information about the fate of the people.
Unlike ordinary priests, the High Priest (Leviticus 21:10-14) was only allowed to marry a virgin who had not before been married. Unlike ordinary priests, who, while not permitted to come into contact with a corpse, were allowed to come into contact with the corpse of a near relative, the High Priest was not allowed to come into contact even with the corpse of his father and mother. The kabbalist Hayyim Ibn Atar, explains this latter rule in an interesting, though unhistorical, comment. The High Priest, by virtue of his elevated role as the totally committed servant of God, had already severed his emotional ties with his parents from the moment he assumed office.
On the basis of Leviticus 16; it is stated in the Talmudic sources that all the services in the Temple on Yom Kippur could be carried out only by the High Priest. No one was allowed to enter the Holy of Holies at any time except the High Priest on this awesome day, when he entered to atone for his people.
It is difficult to know how far all these details developed out of the rules as stated in the Pentateuch or how the Pentateuchal rules themselves were originally formulated, since there is hardly any information about the role of the High Priest in the period of the First Temple. It seems that towards the end of the Second Temple period, under Roman rule, the office of the High Priest was often a political appointment and there are Talmudic references to the unworthiness of the High Priests in this period