Second Ecumenical Council
The roca.org has some notes on the Council. Here's an excerpt:
"One important heresy the Council refuted was. that of chiliasm or millenarianism, taught by a certain Apollinarius. This heresy, based on a misunderstanding of chapter 20 of the Apocalypse, taught that after Christ's Second Coming He would reign on earth with His saints for a thousand years. Some of the heretics described the life of these thousand years as one of bodily pleasures, while others taught of it in a more spiritual way; but all alike taught that it was to be distinct from the eternal Kingdom of Heaven, which would open afterwards."
http://www.roca.org/OA/15/15h.htm
The fine print helps.
I was hoping they weren't calling Justin Martyr a heretic since he, too, was a premillennialist.
It appears they've given themselves some wiggle room in the actual charge against it. "As taught by Apollonarius....bodily pleasures..."