[dread78645]

You have a very poor grasp of church history, my friend. The Gnostics had pretty much vanished long before Constantine's reign.

Wow. Speaking of poor grasp ...

The sects of Valentinus and Basilides were extremely popular until the 4th century.
Marcionites plagued the Church well past the 5th century.
In the west, the Manichean school lasted into the 5th century (St. Augustine was a member for 10 years before he accepted the orthodoxy in 382). It was still active in Persia and Tibet until the 17th century.
A resurgence of Manicheanism spawned the Paulicians of Anatolia and the Cathars of France in the 9th century.

It was the suppression of the Cathars (Albigensian Crusade 1147-1229) that led to the creation of the Dominican Order. After the war the Inquisition was established to root out any remaining heretics. Which it infamously did until the last Cathar was executed in 1321.

The Apostle's Creed was the church creed written to ferret out Gnostics, and it was in use by the early 2nd Century.

Marcionites, and late 2nd Century (Confession of St. Irenaeus 180CE).

[horse_doc]

Not all Gnostics are the same. The first post referred to the original Gnostics that bedeviled the early church, and were pretty much dealt with long before Constantine.

Sure, you can find subgroups of Gnostics staggling on, right up to the present day. But they don't trace their lineage directly to the 1st Century Gnostics, any more than modern druids can trace their lineage back to the old druids. More to the point, they never posed a genuine theological threat to the church after the first century.

Otherwise, Nicea would have been about Gnosticism. And it wasn't - it was about Arianism. Did Constantine "slaughter Gnostics"? Nope.