The magnetism of Ro allowed for floating islands in which Argillian civilization thrived. On an alternate Earth, a colonization effort was sent out to Galileo (Raythe), the first Earthlike habitable planet discovered, in 2049. Several countries including the United States, the Soviet Union, and the European Federation created colonies on Raythe.
The colonists traded with the Argillians, the first alien life discovered, and began to settle the fertile plains of what would be Minstos. However, in 2080, WWIII occurred causing civilization on Earth to collapse and for the Galileo colonists to lose contact. The colonies survived for only another 40 or so years before they began to fall apart without the bulk supplies from Earth, only able to scrap together resources from Raythe. The final blow was when the fertile plain that was settle began to sink into the ocean after a major earthquake. The Argillians did not intervene, and left humanity to die. Only about 1000 people survived, many of them young. Over several generations, the technology and information of Earth was lost and reduced to myth.
Over the next few thousand years, the human population slowly rose and began to spread throughout Minstos, with the first civilizations appearing around the same time in about 1300BD. The first major empire to grow was Warjan, reaching its height in 700BD before internal fighting and and pressure from Northern Interior nations pushed it south and through the Baraith Passage to the Exterior. Another empire that arose around this time was the Varian Empire which was a federation of small kingdoms.
The religion of the people of Raythe was worshiping the moons of Ro and Deaum. Ro was believed to be a heaven where the gods (including the gods of Usa, Ussr, and Uk) lived, while Deaum was an underworld where the daemons resided. The people of Raythe could see the lights of the cities on Ro and knew it to be a heavenly place. Every New Years, the Argillians would light fireworks and celebrate, causing the people of Ro to celebrate and use this as their New Years as well.
At the end of the era, the Argillians were having problems with the magnetic field of Ro. It was weakening and while there was concern, the politics of Ro caused the problem to be ignored until too late. When they realized that they needed to leave the planet, the began work on a space craft that would be able to evacuate them to Raythe, but they were too late. (But not in WIP Alternate History) The floating islands in a chain reaction began to collapse to the shallow sea below, with only several thousand Argillians surviving in nomad tribes on the surface.
The people of Raythe panicked. For a month they saw the fires of Ro burn, and then go dark forever. Empires collapsed, religions split off, and the year numbering system of Before Darkness and After Darkness was created. (Alt.History where Ro fell gradually and people had time to process without revolution)
The power allowed for new nations to take control, such as Minston. While colonization of the New World (the Ilthins, Arthane, and Norvein) began in the 100sBD, it really took off in the 300sAD. This was also when the International League was created under the Ilthin Colonial Charter. The 11th and 12th centuries were a high time for trade with the Silver Trade Roads, created 1000 years prior, gained the nickname the Continental Web because of the immense scale and complexity of trade routes throughout the continent.
Between the 10th and 14th centuries, the Continental Wars raged, in which each country was trying to gain dominance over the entirety of the Minstos continent, ending with Minston, Vichsti, and Natel victories, in which they merged together to form the Minston Republics.
While there was a civil war in the 1500s in which several republics wished to have more power in government, and fighting in the Grand War, the Minston Republics remains the strongest nation to this day.
Map History: http://raythe.org/maps/political/p_1750ad.html