Harmonia was the first planet inhabited by settlers from earth. The planet was considered most like earth in terms of temperature and climate. The original inhabitants called themselves Rheans and came from many different countries of earth. At first Rheans lived as separate territories of earth, affiliating themselves with the continents of North America, South America, Oceania, Europe, Africa and Asia. After a century of living this way, the other known planets in Taurus became inhabited causing the Rheans to decide to unite with one another. By the early 2,700's  3 empires had formed in Taurus and Rhea was still governed by a territorial system. A vote was cast in 2,705 A.D. and it was decided by a majority of the population of the territories that an empire known as Rhea should be formed. It was then determined by vote that the first emperor, a popular politician named Kadmiel, be enthroned as emperor of Rhea.  Rheans decided upon having a democracy that represented each of the territories on Harmonia. A system of civil liberties was also voted upon and passed into law in the empire. Freedom to speak, assemble and worship were part of these rights as was the right to a speedy and impartial trial. 

Upon discovery of the alliance between the empire of Demeter and Hades and finding out that Demeter was increasing its military forces, Rhea responded by forming its own alliance with the empire of the Diodines. As the Diodinians were rich with quality foods, gems, and fine luxury items that Rheans could purchase, the Rheans traded sugar, spices and domestically manufactured goods with the Diodinain such as household items and clothing. As with the Demeterians, Hadians and Diodinians the Theans sold technology, technological products and coffee to the Rheans, in exchange for domestic goods. The Rheans had the advantage of climate and Diodinians and Theans sought to vacation on Rhea. The empire also wanted to defend itself from the empires of Demeter and Hades, in the event of attack, and built up its military, which was soon considered to be the 2nd most powerful behind only the empire of Demeter.

Emperor Kadmiel died in 2,731 A.D. His son Ofael then became emperor. He ruled Rhea for 6 years, however, he was unpopular and was forced to abdicate. Rhea then became a parliamentary democracy.