I can tell you how I view it from my experiences.
There is only one Divinity, the primal source from which all come to be and is divided in to opposites, male and female- or God and Goddess, that work in tandem as one. God, as an emanating force, static and passive, being present and providing, and the Goddess, the active one, having angels under her command and helping souls find their way on the otherworld and here.
All of the other "deities" as we call them (Artemis, Venus, Zeus, Venus- whatever they be or from any of the tradition) are primal archetypes and are a part of our collective unconscious and represent parts of ourselves only with exaggerated traits and energy gathered through thousands of years of belief in them. They are in fact part of ourselves but on a certain level of existence, or consciousness, all of these energies may seem to appear as separate, individual entities.
In this case, praying to Athena for prudence is actually a prayer to that part of ourselves that is prudent and is in this way called out to be more apparent.
However, this is from my point of view, as a future psychiatrist, and from my experiences. I have found out that most all of believes have a common root in something like this.
Hope this helps. :)