Constantine was baptized by an Arian bishop a few years after the Council of Nicaea. His sons were Arians. At least the leadership of the Visigoths that sacked Rome where Arians. That was in 410, only 85 years after Nicea (325).
Yet there were only 2 Arians of 300 Bishops in the Council of Nicea that was convinced enough of Arianism to refuse to sign the Nicene creed.
So why were there so few Arians on the First Council of Nicaea?
In quora people said that the majority of "Arians" were in the west of the empire and hence too far from Nicea. So very few of Arians were in Nicea. Another theory is that Arians were a new idea. I want to know which one is true.
Here are similar questions in quora:
Note: I've heard a theory that most Arian supporters were in the west and Nicea is far away in the east. Also, most Christians at that time, did not consider the Trinity/homoousion a "big thing". They did not think it would concern them. I forget the source.
That is why very few western bishops came in and that explains why Arians were outnumbered. Still, I want to know more about this aspect of history.