One of the leading Gnostics in the last half of the second century was Marcion.
Marcion and the early church father Polycarp had known each other from where they grew up in the east.
When they passed each other on a street in Rome, Polycarp was going to pass without speaking. Marcion stopped him and said, "Don't you know me any more Polycarp?
"Yes," answered Polycarp, "I know who you are. You are the first-born of Satan."
The Church in History by B.K. Kuiper pg 17