There was void. Cold and empty. It was not dark, for there was no concept of light to compare it to. There was just an absence of all things.
Then there was not. Two beings stirred in the void and looked at each other from across the distance. One was a beacon of Light, the other a beacon of Darkness. They were not good and evil, for such things were not yet imagined by mortal or god. The God of Darkness surrounded his Sanctum in Earth to protect it from the harsh light of the other. The God of Light wreathed his Sanctum in flames to protect it from the encroaching darkness.
They saw their creations and were not yet content. They decided that, together they could create something beautiful. A thing of both darkness and light. Together they toiled and worked on the Moon. Before this work was complete, however, it disappeared. There was only the two, so each knew the other was to blame and retreated to his Sanctum to consider what to do next.