The current form of the Creed (sans Filioque) dates to the 1st Council of Constantinople in 381. So yes, I'm quite familiar, and I confess it frequently and enthusiastically.
False. The Council of Nicea held in 325 was convened in order to settle the Arian controversy; it is true that the emperor Constantine summoned the bishops all over the empire to come and participate in the council (he hoped that such a meeting of bishops would resolve the theological conflict caused by the teachings of Arius). The council bishops eventually all, but three, affirmed the homoousion formula over and against the homoiousian and heteroousian formulas put forward by the Arians and Arian sympathizers; and put forward the first form of the Nicene Creed. However, it didn't settle the issue, and Constantine himself was eventually swayed to the Arian side, which rejected the Council of Nicea, and a number of pro-Arian councils followed. Constantine, ultimately, died a baptized Arian (or, rather, was baptized on his deathbed by Eusebius of Nicomedia, an Arian).
There was no "joining" with the Roman government involved.
Doubly false. The Roman Catholic Church is so-called because of the episcopal see at Rome, and more specifically because of the Roman (or Latin) Rite of the liturgy. There was no "Roman Catholic Church" until the Great Schism in 1054, 700 years after Constantine.
No it didn't.
I believe in one, holy, catholic and apostolic Church.
I've been listening to credible historians and academics. I'm curious who you've been listening to to.
-CryptoLutheran