An anonymous reader asked: Why are the witings of St. Irenaeus now so suddenly important[?] I thought that his relics were sacked by the Calvinists becaused he was alleged to be a heretic, ie., he is a proponent of Free Will and that his other writings do not support TULIP.
The importance of Irenaeus is merely historical. In many ways, Irenaeus is notable more for what he did not say, than for what he did say. Of course, we have only a limited amount of what he wrote and said, but what we find in those writings is some amount of evidence as to what was believed and held in his day. The process of preserving his writings has not been unbiased, and has been subject to some serious "selection" concerns. Nevertheless, considered with the appropriate caveats, Irenaeus gives us a picture into the mind of some Christians of the late 2nd century.
It (Irenaeus' writings) is not infallible, and it is not our rule of faith, but it is interesting - just as the writings of Calvin and Aquinas are interesting but not the rule of faith.
Irenaeus' alleged remains disappeared when Calvinists destroyed a shrine where they were supposedly held. Whether they were actually there or not, we cannot know with certainty. Why the shrine was destroyed is better assigned to the fact that Calvinists oppose the veneration of the dead, more than any antipathy for the teachings of Ireneaus on any particular point. Unfotunately, as far as I know, the details are sparse as to any stated reason for the shrine's destruction, and no information regarding what happened to the interred remains has come to light in subsequent years.
One would not be surprised if the Calvinists simply buried Irenaeus' remains in an unmarked grave to prevent further idolatry, just as the bronze serpent was piously destroyed by Hezekiah (2 Kings 18:4) because people had come to venerate it.