The subject of the condemnation of premillennialism by an ecumenical council has been prominent in some recent discussions here, so I thought I'd repost some of my comments on the subject from another thread. Jnorm888, an Eastern Orthodox, originally claimed that premillennialism was condemned as a heresy by an ecumenical council in the sixth century. He later retracted that claim and replaced it with the claim that the doctrine was condemned by the First Council of Constantinople in the fourth century. NPMcCallum, another Eastern Orthodox, also argued for a condemnation by First Constantinople. Here, below, is my latest response to NPMcCallum on the subject, from the thread here.
"Jason, I would agree with you 100% if it were not for 'whose kingdom shall have no end.' 'Whose kingdom shall have no end' is the ONLY phrase added to the Christological portion of the creed at Constantinople, the same council which condemns a known chilliast (and I think two known chilliasts, if I can find the source). Why add this phrase to the Creed? There is no other context for this phrase other than chilliasm. I'll happily accept correction if you can show otherwise."
As I explained earlier, I don't know much about the history of the creed in question. I don't know the timing of the addition you're referring to or much else about its background. I know there's been disagreement among scholars regarding where different portions of the creed came from. I haven't followed those disputes in detail.
You've made a lot of assertions, but the only source you've cited so far has been a letter of Gregory Nazianzen, which mentions premillennialism, briefly, as one of the beliefs of some of the heretics in question. It wasn't the central belief of those heretics, and the council itself condemns multiple groups of heretics without any reference to premillennialism. If the phrase in question in the creed came from the council, and the council meant to condemn premillennialism of some type, I would want more evidence before concluding that a condemnation of premillennialism in general was in view. As I said before, an allusion to Luke 1:33 doesn't contradict premillennialism as it's commonly perceived, so the phrase itself shouldn't be seen as a condemnation of premillennialism. You would need to combine the phrase with something else indicating that a condemnation of premillennialism was in mind.
Philip Schaff writes, concerning this addition to the creed:
"This addition likewise is found substantially in the Antiochian creeds of 341, and is directed against Marcellus of Ancyra, Sabellius, and Paul of Samosata, who taught that the union of the power of God (ἐνέργεια δραστική) with the man Jesus will cease at the end of the world, so that the Son and His kingdom are not eternal Comp. Hefele, i. 438 and 507 sq." (source, note 1441)
That heresy isn't part of premillennialism in general. As I said earlier, a condemnation of a heretical form of premillennialism wouldn't qualify as a condemnation of premillennialism in general. You have to attach a heresy to premillennialism that isn't part of premillennialism itself in order to place some form of premillennialism under this condemnation.
You say that "there is no other context for this phrase other than chilliasm", but Schaff's comments above provide another context. The eternality of Christ's reign is relevant to heretics who denied that Christ and His reign are eternal. No condemnation of premillennialism in general is needed to make sense of the creed.
Of the scholars I've read on the history of premillennialism so far, none have argued that the doctrine was condemned by the First Council of Constantinople. And as I noted earlier, the doctrine continued among mainstream Christians after First Constantinople. Furthermore, whoever composed the portion of the creed you're referencing probably realized that premillennialism had been a widespread belief, accepted by the likes of Justin Martyr and Irenaeus. In light of such factors, a condemnation of premillennialism in general seems unlikely. The evidence I've seen so far is against your conclusion.