In Roman Cosmology, the Sky is the traditional province of the Dii Consentes (The Council of Twelve Gods). In the Roman mind, the powers of the Sky were just and right. The Romans sought to divine the will of the Dii Consentes from birds in flight and other sky omens. Iuppiter, Optimus and Maximus (Jupiter, the Supreme Sky God) signaled His Will through thunder and lightning.
In Rome, the Sky Power supported civic society. Iuppiter’s temple was the center for Roman politics. Victorious generals made sacrifices there as well. In the Roman worldview, the Sky Gods with the Senate and the People governed Rome.
Meanwhile, the Earth was the province of the Dis Pater, God of the Underworld. Under His Rule, the earth is chaotic and dark. For that reason, the Mundus (Well to the Underworld) is only opened three times a year. Once the Mundus is opened, Dii Inferi (The ‘Infernal Ones”) move about. For that reason, these days are considered to be unlucky.
However, the Earth Power used sacred snakes to convey prophecies to to the people. Caves and grottos were his sacred places. The Dis Pater not only ruled the Underworld but also governed wealth and riches. Meanwhile, the Penates, guarding the family’s food stores, lived in underground chambers.
In the Roman sense, the mingling of the Two Powers is one of order working with chaos. Snakes, associated with various Gods, crawled out of caverns offering omens. Lightening bolts from the skies were more signals of Divine Will. The powers of Earth and Sky mingle, but then separate.
As the Sky and Earth Powers mingled, it was for the good of the Roman people. The Sky brought the governing power and the Earth brought riches and kept people safe. Together, they supported the people of Rome.