There are several very curious usages practiced by the married priest. He is recruited from all classes of society, but more often there is a succession from father to son. [114] The conditions demanded, besides parochial election, are acquaintance with ecclesiastical and liturgical matters, an exemplary life, and the consent of his wife. After his ordination he must fast for forty days. He then prepares himself for his first mass by a life of retreat in the church, restricting himself to a vegetable diet for twenty-four hours. [115] The wife, who enjoys a certain precedence in society, observes a customary abstinence in the absence of her husband. One week or at least three days before the celebration of the mass, he keeps away from home, passing the nights within the church. He may engage in domestic or even professional work so long as this does not interfere with the duties of his calling. Should his wife die, he may not marry again unless he lays aside his priestly robe, nor may a priest ever marry a widow. These practices are not dead letters, except that the custom of sojourning within the church for three nights before mass has, in Constantinople at least, been reduced to a single night. The bishops are chosen as chiefs of dioceses by the council of the diocese, six sevenths of whose members are laymen, the remainder being ecclesiastics. [116] The patriarchs, including the Katholikos, the supreme authority of the church whose seat is at Etchmiadzin, the religious center of the nation, are chosen by an electoral assembly of the religious heads (bishops or archbishops) and lay deputies who are nominated by the dioceses as a whole. [117] The eight members of the synod, which is an advisory body to the Katholikos, and the seven oldest members of the congregation at Etchmiadzin have equal share in voting. The electoral assembly, so constituted, chooses two candidates, one of whom is selected by the Czar. The Czar, after his selection is made, sends a deputy to meet the successful candidate, who is decorated and escorted with due ceremony to Etchmiadzin where he is officially ordained. There are only two patriarchates besides the see of Etchmiadzin, i.e., those of Constantinople and Jerusalem. The corresponding patriarchs are likewise chosen by a national assembly, six sevenths of whose members belong to the laity. The patriarchs of both Jerusalem and of Constantinople acknowledge the supremacy of the Katholikos of Etchmiadzin, who is thus head of the church, though not infallible.