The Trisagion…er…Tersanctus?

Here’s a bit of a curiosity.

I’m currently working on a brief review of Larry Hurtado’s At the Origins of Christian Worship, as well as a study of liturgical acclamations and doxologies in the ancient Christian church. I began my research for the latter with a review of Paul Bassett’s entry on “Doxology” in the Encyclopedia of Early Christianity (2nd ed). Bassett makes a definite distinction between two similar doxologies of the early church:

In the fourth century, three principal forms of liturgical doxology became distinguishable. Probably the oldest is the Sanctus or Tersanctus, first notice of which comes from the end of the first century. Its original form was probably “Holy, Holy, Holy, Lord of Hosts, all creation is full of thy glory” (1 Clem. 34)In the eastern liturgies, after the mid-fifth century, the term “Angels’ Hymn” often referred to quite another doxology, the Trisagion: “O holy God, O holy mighty One, O holy immortal One, have mercy on us.”…It entered western liturgies only in the mid-sixth century or later, in the wake of Justinian I’s attempts to restore the old empire.

To Bassett, the Sanctus and Tersanctus represent the same ancient doxology, while the Trisagion represents a similar but distinct doxology. While wrapping up Hurtado’s book and beginning to work on my review, however, I stumbled across this bit toward the end (p.113):

As we noted in our discussion of early Christian worship conceptions and practice, from the New Testament onward there is the notion that worship should be understood as an earthly participation in a heavenly reality. In chapter two, I noted that this sense of participation in heavenly worship lies behind the traditional phrasing ‘Wherefore, with angels, archangels and all the company of heaven we laud and magnify your glorious name’, wording which introduces the congregational recitation or chanting of the ‘Trisagion’ (Greek for ‘thrice holy’, taken from the song of the heavenly creatures in Isaiah 6:3) in the liturgical traditions of Christian Eucharist.

Here, Hurtado appears to be referring to as the Trisagion what Bassett refers to as the Sanctus/Tersanctus. I am aware that the words Tersanctus (Latin) and Trisagion (Greek) are synonymous, and that their similar content (lots of holies!) might lead anyone to confuse the two. I was also familiar with the same use of the title Trisagion as Bassett, but had never heard it used interchangeably with the Tersanctus. Both the Tersanctus and the Trisagion feature the same threefold glorification of God, but are quite different in their purpose and style.

To make things even more confusing, Wikipedia offers the suggestion that the Trisagion and Tersanctus are in fact the same doxology, while the Sanctus refers to the doxology taken from Isaiah 6:3 (mentioned by Hurtado above as the Trisagion).

So which is it? Is the Trisagion the Trisagion and the Sanctus synonymous with the Tersanctus, or are the Trisagion and Tersanctus synonymous while the Sanctus refers to a different doxology? Also, can you repeat that sentence back to me? I’m not sure I even understood it.

Admittedly, this is probably a question that could be answered quite easily with a bit more research. But since I’m a bit pressed for time on other studies these days, I thought I’d just leave it for you to ponder.