"Originally, the pyramid was faced with a harder, white sandstone than the main blocks. The top of the pyramid was crowned with a gilded stone – a pyramidion. The facing shone in the sun with a peach color, as if it were a 'shining wonder to which the sun god Ra himself seemed to have given all his rays'."
So, I suggest naming the upgraded Pyramid: "Haven of Ra".
Even though Ra isn't mentioned anywhere in Heroes 5, where there is sun, there is Ra.
Haven of Ra....