From the codex:
The Divine is the titular head of the Chantry, although since the schism split the Imperial Chantry into its own faction there are now in fact two Divines at any one time. One Divine, informally called the White Divine, is a woman housed in the Grand Cathedral in Val Royeaux. The other, known as the Black Divine, is a man housed in the Argent Spire in Minrathous.
Neither Divine recognizes the existence of the other, and the informal names are considered sacrilegious. No matter the gender, a Divine is addressed as “Most Holy” or “Your Perfection.”
Beneath the rank of Divine is the grand cleric. Each grand cleric presides over numerous chantries and represents the highest religious authority for their region. They travel to Val Royeaux when the College of Clerics convenes, but otherwise remain where they are assigned. All grand clerics are addressed as “Your Grace.”
Beneath the grand cleric is the mother (or, in the Imperial Chantry, the father). If a mother is in charge of a particular chantry, “reverend” is appended to her title. These are the priests responsible for administering to the spiritual well-being of their flock. A mother or revered mother is addressed as “Your Reverence.”
Brothers and sisters form the rank and file of the Chantry and consist of three main groups: affirmed, initiates, and clerics. Affirmed are the lay-brethren of the Chantry, those regular folk who have turned to the Chantry for succor. Often they are people who have led a difficult or irreligious life and have chosen to go into seclusion, or even orphans and similar unfortunates who were raised into the Chantry life. The Affirmed take care of the Chantry and are in turn afforded a life of quiet contemplation, no questions asked.
Only those folk who take vows become initiates. These are men and women in training, whether in academic knowledge or the martial skills of a warrior. All initiates receive an academic education, although only those who seek to become templars learn how to fight in addition.
Clerics are the true academics of the Chantry, those men and women who have dedicated themselves to the pursuit of knowledge. They are often found in Chantry archives, sages presiding over libraries of books and arcane knowledge. The most senior of these clerics, placed in charge of such archives, are given the title “elder,” although such a rank is still beneath that of mother. All other brothers and sisters are addressed simply by noting their title before their name, such as “Brother Genitivi.”
—From a guide for ambassadors from Rivain.