The Council in Trullo (Quinisext Council, 692 AD)

Since we have learned that in some churches deacons hold ecclesiastical offices, and that hereby some of them with arrogancy and license sit daringly before the presbyters: we have determined that a deacon, even if in an office of dignity, that is to say, in whatever ecclesiastical office he may be, is not to have his seat before a presbyter, except he is acting as representative of his own patriarch or metropolitan in another city under another superior, for then he shall be honoured as filling his place. But if anyone, possessed with a tyrannical audacity, shall have dared to do such a thing, let him be ejected from his peculiar rank and be last of all of the order in whose list he is in his own church; our Lord admonishing us that we are not to delight in taking the chief seats, according to the doctrine which is found in the holy Evangelist Luke, as put forth by our Lord and God himself. For to those who were called he taught this parable: “When ye are bidden by anyone to a marriage sit not down in the highest room lest a more honourable man than thou shall have been bidden by him; and he who bade thee and him come and say to thee: Give this man place, and thou begin with shame to take the lowest room. But when thou art bidden, sit down in the lowest place, so that when he who bade thee cometh he may say to thee, Friend go up higher: then thou shalt have worship in the presence of them that sit with thee. For whosoever exalteth himself shall be abased, and he that humbleth himself shall be exalted.” But the same thing also shall be observed in the remaining sacred orders; seeing that we know that spiritual things are to be preferred to worldly dignity.

Ancient Epitome of Canon VII.

A deacon in the execution of his office, if he shall have occasion to sit in the presence of presbyters, shall take the lowest place unless he be the representative of the Patriarch or bishop.

Balsamon, Zonaras, and following them Van Espen point out that this canon is a relaxation of the XVIII. Canon of Nice which punishes presumptuous deacons not only with loss of rank in their grade, but also with expulsion from their ministry.

Van Espen well remarks that the Fathers of this synod had in mind not only the preservation of the distinction between deacons and presbyters, but also between those in ecclesiastical orders and those enjoying secular dignities with regard to ecclesiastical matters, but who were not to gain there from ecclesiastical precedence. This is what is meant by the last clause of the canon.

Beveridge gives a list of these quasi ecclesiastical dignitaries as follows: Magnus Œconomus, Magno Sacello Præpositus, Magnus Vasorum Custos, Chartophylax, Parvo Sacello Præpositus, Primus Defensor.