In an attempt to expand the history of the Sailor Moon universe, I present a story of the Earth Kingdom. The version of the history that I choose to expand is the one presented in the English translation of the Sailor Moon manga by Naoko Takeushi, with additional details from the DiC release of the syndicated TV show. The rest comes from my imagination and draws from the actual world history of 900-1000 AD. Since I am using the English translation of the manga as my main reference, the names I use are the translations of the names used there. Additional names come from the TV version released in North America by DiC.
The story takes place during the uprising of war against the Moon Kingdom that occurred approximately 1,000 years ago. I place the Earth Kingdom as a world existing in (a fictional version of) Japan that is almost completely removed from the human kingdoms it shares the planet with. Japan is experiencing the end of the early Heian period and the capital city of its loose confederacy of 5 million people is located in Heian-kyo (modern-day Kyoto). But this and the struggles of the Heian dynasty are of little concern to the Earth Kingdom, a kingdom of super-humans who originated from the kingdom of the Moon thousands of years ago.