|Christ died so we could write articles on|
- God just is - the unbegotten
- Jesus takes a back seat having been made by god - the begotten
- God, working through Jesus cooked up the Holy Spirit as a sort of helper to the both of them
The net result of this is that god is top of the tree and the only true god. Jesus and the Holy Spirit are very much "also rans."
Believing in Arianism is very third century and, back then, was pretty heretical. It got thrown out as a belief at the Council of Nicaea (325 CE) but sort of crept back in again at the Council of Constantinople (385 CE). It's a distinction that is important to some after they've finished counting the angels dancing on a pinhead.
This belief got Giordano Bruno into a lot of trouble.
 See also