Subdeacon

A subdeacon assists at the liturgy in ways that stop short of the deacon's own ordained ministry: vesting the bishop during hierarchical services, a task requiring detailed familiarity with the sequence and symbolism of episcopal vestments, holding liturgical implements such as the dikirion and trikirion, the paired and triple candlesticks a bishop uses to bless the congregation, and generally assisting at the altar during services a bishop celebrates. The rank sits at the boundary between the laity and the ordained clergy proper: subdeacon is conferred through a rite of ordination distinct from, and less than, diaconal ordination, and a subdeacon, unlike a deacon, may not enter the sanctuary during the consecration of the Eucharist or perform functions reserved to the three major orders of bishop, priest and deacon.

Historically the subdiaconate was one of several minor orders forming a graded ladder of clerical formation in both Eastern and Western Christianity; the Roman Catholic Church abolished the subdiaconate as a distinct order following the Second Vatican Council's reforms, while Orthodox churches have retained it as a living rank still conferred today, particularly on men assisting regularly at hierarchical services or preparing for eventual ordination to the diaconate or priesthood.

Subdeacon sits at the top of what Western canon law once called the minor orders, a set of lesser clerical ranks, including porter, lector, exorcist, and acolyte, that a candidate for priesthood traditionally passed through on the way to the major orders of deacon, priest, and bishop. The Latin Church abolished the subdiaconate as a distinct order after the Second Vatican Council, replacing the old sequence with the two instituted ministries of lector and acolyte for seminarians and lay ministers alike, but Eastern Christianity, including the Eastern Catholic churches that share the Byzantine liturgical tradition, kept the subdiaconate as a living rank.

In the Byzantine rite a subdeacon is ordained through the cheirothesia, a blessing given outside the sanctuary rather than the cheirotonia performed at the altar for deacons, priests, and bishops, marking it as one degree lower in the hierarchy than the three sacred orders proper. Traditionalist Catholic communities that retain the pre-conciliar Latin liturgical books have also preserved the subdiaconate as they understood it before the reform, so the office continues in more than one living form even where the mainstream Latin Church discontinued it.