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 there were so few Arians on the First Council of Nicaea?
In quora people said that the majority of "Arians" are 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: http://www.quora.com/Why-were-Arians-underrepresented-at-the-First-Council-of-Nicaea http://www.quora.com/How-was-the-representation-of-bishops-at-the-Council-of-Nicea-determined
Note: I've heard a theory that most arian supporters are in the west and Nicea is way in the east. Also, most christians at that time, do not consider trinity/homoousion a "big thing". They do not think it'll concern them. I forget the source.
That is why very few western bishop coming in and that explain why Arians were outnumbered. Still I want to know more about this aspect of history.