This valuable page needs to be seen. The Easter Sepulcre in the Sarum Use and other medieval rites is not the same thing as the Altar of Repose in the Roman rite.
It is unclear in the Use of Sarum what is done with the Blessed Sacrament after the Maundy Thursday Mass and the stripping / washing of the altar, after which there is the Maundy – the washing of the feet in the chapter house. Possibly the two hosts are simply put back into the hanging pyx. On Good Friday, just before the Mass of the Presanctified, all the rubric says is that the sacrifice is placed on the altar in the accustomed way and censed. There is no evidence of a procession like in the Roman rite. The Pie also seems to be parsimonious. If anyone has information from other sources, I would be grateful.
Fr Aidan Keller, an Orthodox priest, is of this opinion:
Since the question is a Sarum use one, I have a Sarum use answer. The Easter sepulchre is not “inhabited” by any reserved sacrament until after the Presanctified Mass on Good Friday. At the end of that service, as Communion-time Vespers ends, there is the procession to the sepulchre with the cross, then the placing of the reserved sacrament in the Easter sepulchre. On Maundy Thursday, the sacrament is reserved in the usual way which is most often the hanging dove (a reservation aumbrey set into the wall is also known). A tabernacle on the altar is not used. The vestments colour is red. The altar is stripped and washed in water and wine, with special twig brooms, on Maundy Thursday, and is not re-vested until daytime on Holy Saturday, so it is not vested at the time of the Presanctified Mass.
Fr Sean Finegan says the following in Sarum Maundy Thursday:
As to what happened to the Blessed Sacrament, whether it was placed in an altar of repose, or in the sepulchre, or simply returned to its usual place of reservation, the books I have are silent.
After I wrote this post, I discovered a reference to the third Host being brought from the ‘Altare Authentica’ to bury in the sepulchre on Good Friday. This altare authentica is probably to be identified with the high altar, and therefore we assume that there is no altar of repose, but that the Blessed Sacrament is simply reserved at, or over, the high altar as usual. The ceremonies that we associate with the altar of repose are observed the following night, then, at the sepulchre.
I put them into a wooden urn on a simple credence table on the Gospel side of the sanctuary like the Roman altar of repose. This will become the Easter Sepulcre, but as yet is merely a place to reserve the Blessed Sacrament without ceremony. The only alternative seems to me to reserve in the hanging pyx, which doesn’t seem quite right.
On Good Friday, this arrangement with the remaining (third from Maundy Thursday) host is veiled as the Easter Sepulcre. Now the rubrics are clear!
The cross that is “buried” with the Blessed Sacrament is that used on Good Friday for the creeping to the cross. It is a large and austere wooden cross with a corpus. I cover it over with a veil.
The medieval sepulcre was a permanent structure in the wall of the church or some kind of wooden box. After the Good Friday Mass of the Presanctified, the “burial” is accompanied by the singing of the responsory I am counted as one of them that go down into the pit. Thus, in the Use of Sarum, the church is not totally bereft of the Presence on Holy Saturday. The symbolism is different from the Roman usage of having the church “die” on that day.
The Easter Sepulcre is watched like the Roman altar of repose, except a day later. On Easter Sunday morning, before Mass and the ringing of the bells, the Blessed Sacrament is taken to the altar with ceremony and chant, and put back into the hanging pyx. The cross is also removed with a procession. Then the Mass of Easter Sunday is celebrated.