Page "Eusebius of Nicomedia" Paragraph 4

At the First Council of Nicaea, 325, he signed the Confession, but only after a long and desperate opposition in which he " subscribe with hand only, not heart " according to ancient sources.

It was a huge blow to the Arian party since it was surmised that the participants in the First Council of Nicaea were evenly split between non-Arians and Arians.