Speratus,

Calvinists uphold the Athanasian Creed and the hypostatic union.

As far as the clause, "not by the conversion of the Godhead into flesh, but by taking the manhood into God," I understand it to mean that the divine nature did not become fleshly nature, but rather took a fleshly nature and united it to itself. In this way both the divine and fleshly natures remained wholly intact.

Kyle

I tell you, this man went down to his house justified.