Where are you getting this information?

The Arian heresy actually didn't impact the Western half of the Church.  In fact most of the heresies primarily effected the East.  

Rome didn't believe Jesus was God?  That is a vague statement.  Specifically what are you talking about?  Are you talking about Liberius who arguably signed on to the Arian Creed?  What specifically? If so--he did that under threat of persecution and so cannot be taken seriously.