While in our parishes of the Greek Orthodox Archdiocese of Australia, the Sacrament of Holy Unction is administered on Great and Holy Wednesday afternoon, our Monasteries all administer it on Great and Holy Thursday morning with Orthros and the Liturgy of St. Basil. I noticed that the same was done on the Holy Mountain. Is this simply a monastic custom or is it in fact an older custom to administer Holy Unction on Holy Thursday?
Very interesting. I wonder if that is what is called for in the Typikon of St. Savas. At what point during the Orthros and Liturgy of St. Basil is Holy Unction administered? Is the entire service, starting with its own "Blessed is the Kingdom" celebrated, or is it some kind of anointing like unto that which one often finds during monastic vigils?
In Greece, Holy Unction is administered on Wednesday afternoon
and then the final Service of the Bridegroom occurs in the evening. In the U.S., however, we typically replace the final Bridegroom with Holy Unction. Some parishes have one Holy Unction at, say, 4 p.m. and then a second one at 7 p.m., thereby enabling more people to attend, depending on their work schedule.
As to the history: anointing with oil has many meanings and has had different associations through the centuries. Origen and St. John Chrysostom mention that penitents were received back into the church by means of a public anointing -- something that very likely occurred during Holy Week. So, very early on, it is typically associated with forgiveness of sins and reception into the fold, allowing the person admittance to the Holy Chalice. (This is also why chrismation was a typical way of receiving heterodox into the church). We have a full-fledged unction prayer along these lines as early as the Euchologion of Serapion in the mid 300s.
Very soon thereafter, though, perhaps because of the demise of official roles for penitents, we see the public anointing with oil mainly associated with the healing of sick and forgiveness of sins. Again, it is still always tied in some way to approaching the Holy Chalice -- kind of a double whammy to take care of all sickness, body and soul. It became a pretty elaborate ritual, involving seven priests, and apparently was popular in the many churches that had hospitals attached to them. The sources from the renaissance of the Komnenian period reveal that Holy Unction would take place over a seven-day period. The people would carry the sick from the nearby hospital into the Nave, the seven priests would hold an all-night vigil for seven days in a row, then each would read one of the prayers of blessing of the oil, after which they would concelebrate the Divine Liturgy and anoint everyone laying on the floor of the nave. Even at this late point (11th - 12th century), there was this connection between Unction and Holy Communion. I would guess this is where the Athonite practice comes from, especially since as late as the 1400s, St. Symeon of Thessalonki said that everyone was required to be anointed with holy oil or they wouldn't be allowed to approach the Holy Chalice. Obviously, that element of the Cathedral Rite tradition hasn't persisted, but perhaps the Athonite practice is a little liturgical echo of it. Although, I suppose you could say that having Holy Unction the day BEFORE St. Basil's Liturgy is even more in line with that older understanding.
My feeling is that Holy Unction was to the late antique and medieval Church what Holy Confession became to the Slavic church in the early modern period (after the tremendously influential tenure of the Western-educated Metropolitan Peter Mohyla).
So, according to either the ancient understanding (penitential leading to communion) or the late antique/medieval (healing/forgiveness of sins leading to communion), it makes good sense to have Holy Unction during Holy Week.