The Silver Millennium was a peaceful time period during the prehistoric age when the Moon Kingdom existed in harmony, along with the rest of the planets of the Solar System. It provides a setting for the past lives and future selves of most of the series' major characters, and functions as a major driving force behind both plot and characterization.
The royal family of the Moon Kingdom during the Silver Millennium bear on their foreheads special markings shaped like small crescent moons. These appear on Queen Serenity, Princess/Neo-Queen Serenity, and Chibiusa Small Lady, as well as Sailor Venus when disguised as the princess and the moon cats - Luna, Artemis and Diana. In the anime, non-royal civilians of the Moon Kingdom lack the symbol on their foreheads.
Silver Millennium Kingdoms
The Moon Kingdom, though it had a fairy-tale appearance, demonstrated an advanced technology. It existed within a dome which produced an artificial climate, and had an advanced computer called the "Eternity Main System". According to Artemis, ice skating was a popular sport. The original anime showed Princess Serenity being very good at ice skating. Those who resided in the Moon Kingdom were long-lived beings and had two specific duties: First, they were to protect the Silver Crystal, a powerful "holy stone" which had been handed down through the generations. Second, they were to watch over the evolution of Earth and protect it from any negative influence.
The original Silver Millennium, which existed thousands of years ago, is portrayed as an ancient Golden Age, marked by peace, prosperity, and good relationships between the people of Earth and Moon. The Moon Kingdom itself, ruled by Queen Serenity, centered in Mare Serenitatis (the Sea of Serenity) was also home to Princess Serenity and her four guardians, later to be known as the Sailor Senshi. The Outer Senshi, Sailor Uranus and Sailor Neptune, were guardians who had defended the Moon Kingdom from invaders from beyond the solar system, while Sailor Pluto protected the Time Gate. The Outer Senshi had stayed in separate, of the Moon Castle with their talismans.
During this era Endymion, flanked by his four guardians, held the position of First Crown Prince of Earth. Despite a prohibition on relations between people of the Earth and the Moon, he and Princess Serenity fell in love.
The Dark Kingdom was ultimately responsible for the fall of the first Moon Kingdom. Out of jealousy and under the influence of the evil Queen Metalia, a sorceress named Beryl raised up the citizens of Earth in a war against the Moon. As a result, the Moon Kingdom was completely destroyed, with Prince Endymion, Princess Serenity and her guardians all dying in the battle. The war was the end of the First Silver Millennium.
In the manga, the Outer Senshi, who were not present at the fight, were drawn to the destruction of the Silver Millennium, where their talismans unleashed a hidden power, which awakened Sailor Saturn, who lowered the Silence Glaive and destroyed the remains of the Silver Millennium, and all who survived, including herself. Everyone was reborn into the present day as a result.
In the anime, when it seemed all hope was lost, the Queen used the Silver Crystal to seal away the Dark Kingdom's powers and sent her daughter, Prince Endymion, and the Guardian Senshi to be reborn on Earth during the 20th century. This all came at the cost of her own life though.
The prince and princess were reincarnated as Usagi Tsukino and Mamoru Chiba and even before they recovered their memories, they succeed in finding each other once again. The reincarnated Sailor Senshi become close friends with Usagi; through their efforts, the reinstated Dark Kingdom and even Metalia herself are destroyed.
In the manga and the second anime adaption, the Moon Kingdom and its castle are resurrected at the end of this conflict, but Usagi decides to continue living on Earth, with her parents and with Mamoru. This wasn't the case in the original anime, however. Mamoru and the Sailor Senshi continue living their normal lives on earth, while protecting the universe from new enemies in the future.
Both the anime and the manga reveal that a new Silver Millennium will exist in the 30th century, centered in the city of Crystal Tokyo. Usagi and Mamoru will rule it under the names of Neo-Queen Serenity and King Endymion, and they will have a daughter named Princess Usagi Small Lady Serenity. The Earth becomes a world wide kingdom once again.
The Guardian Senshi protect the entire royal family. However, the story makes no mention of the location of the Outer Senshi, other than Sailor Pluto. This is likely because the Crystal Tokyo storyline was created before the introduction of the Outer Senshi. After their awakening in the manga, the Sailor Quartet also act as guardians, but to Small Lady. Luna, Artemis, and Diana live in the palace as well. The Black Lady Musicals (but no other canon) show that the Outer Senshi are around during this time and help the Senshi of the present fight the Black Moon Clan.
At the center of the kingdom stands the Crystal Palace, where the Royal Family and the Guardian Senshi live. The manga depicts it over water, while in the anime it has another palace, Serenity Palace, located at the top middle spire. It is particularly shown in the beginning credits for the second opening sequence of Sailor Moon R, and is seen in a flashback where Chibiusa thinks that the Guardian Senshi and her parents have forgotten her birthday. Later, the interior is shown, indicating that this is the part of the Crystal Palace where the Royal Family and their protectors live.
Exposure to the Silver Crystal renders all of Earth's inhabitants functionally immortal. Anyone not born in Crystal Tokyo becomes essentially locked at their current physical age, as shown by the Queen and King Endymion and the Guardian Senshi court, who all appear as if aged in their early twenties. Anyone born in Crystal Tokyo has a slow growth-rate – Small Lady, for example, is stated in the manga to be over 900 years old, yet has the body and mind of a child. According to her parents, such an extremely slow growth is irregular, and Chibiusa's extended childhood is an important part of the fourth plot arc.
Like the first Silver Millennium, the second Silver Millennium also got attacked, this time by the Black Moon Clan. After Neo-Queen Serenity expelled the Black Moon Clan to the fictional planet Nemesis, the tenth planet in the Solar System, Wiseman took this as an opportunity to achieve his goal of bringing total darkness to the world and unleashing the full power of the Death Phantom. He manipulated all members of the Black Moon Clan to unknowingly support his self-interest, encouraging them seek vengeance on Neo-Queen Serenity and destroy Crystal Tokyo.
The Black Moon Clan launched an attack on Crystal Tokyo. Sailor Pluto sent the daughter of Neo-Queen Serenity and King Endymion to the past for safety. Chibiusa was followed by the Black Moon Clan but was protected by the Sailor Senshi of the 20th Century. The Sailor Senshi learn of their futures when traveling to 30th Century Crystal Tokyo and defeat the Black Moon Clan in the present day, restoring the future.
Though Serenity has taken her place as Queen on Earth, Takeuchi leaves it unclear whether she returns to the Moon as Neo-Queen Serenity to re-establish herself as the new monarch of the Moon Kingdom itself. Although Crystal Tokyo was decimated thanks to the princess foolishly taking her mother's crystal, Small Lady was not banished or sentenced to death for the theft.
Queen Serenity was the ruling monarch of the Moon Kingdom and mother of Princess Serenity (during the first Silver Millenium) and maternal grandmother of ChibiUsa (Small Lady). Queen Serenity occasionally appears as a guide to help the Sailor Senshi to remember who they are through Luna. She states that the people on Earth knew her as the Moon goddess Selene.
She was a wise and good ruler. Having physically perished long ago, she appears only in spirit, as a sort of hologram. She tells the Senshi about their past lives, and about the history of the Moon Kingdom. In flashback, she is shown speaking the name of the Crystal (or, in the dub, "Cosmic Moon Power") to send her daughter and the others to be reborn in the future; she also uses Moon Healing Escalation, a power inherited by Sailor Moon. After this encounter, she appears just once more to give Sailor Moon a new transformation brooch and rod.
Queen Serenity first appears in Act 10 of the manga. As in the anime, she appears as a hologram, and specifically mentions having saved her spirit within the Eternity Main System in order to preserve her will. The Senshi begin to remember their past as she describes them, and tells them that they must find Metalia, who has escaped the seal placed on her and gone into hiding on Earth. Later, Queen Serenity's spirit appears in the reconstructed Moon Kingdom, telling her daughter to find happiness with the one she loves. She appears three times more, all in flashback: once in Sailor Pluto's memories, after the birth of Princess Serenity; confronted by Queen Nehellenia, and visiting the Galaxy Cauldron.
It is unclear where she is from although it is known that she is not from the moon but a distant universe, the same from which Queen Nehellenia came from.
Queen Serenity does not appear in the live-action series but does appear in its "Special Act".
Prince Endymion of earth is the only known male associate of the Silver Millennium, during which he first developed a relationship with Princess Serenity. During the reign of Crystal Tokyo, he would claim the title as King Endymion.
Act 41 of the manga reveals the Sailor Senshi as princesses of the Solar System. Each one had her own castle, which she can call upon late in the series for power. This act first enables Sailor Moon to transform into Eternal Sailor Moon. The castles are named after moons of the respective planet, except for Mercury's and Venus'. Venus' castle is introduced long before the others', in the Sailor V manga, but she never mentions this to them.
In Act 45, Sailors Uranus, Neptune, and Pluto actually visit their castles — huge structures orbiting around their respective planets. Each castle features viewscreens, forcefields, comm systems, and other forms of high technology and comes under the protection of a Power Guardian, who appears as a miniature version of the Senshi she serves. Sailor Pluto states that the castles were given to all the Senshi by Queen Serenity at the time of their birth.
Takeuchi's Materials Collection artbook shows the detailed design of each princess's unique gown. The Senshi wear the gowns at key moments in the Stars manga, and also in the Original Picture Collection Volume IV. Flashbacks to the Silver Millennium, however, always show them dressed in their ordinary uniforms.
Sailor Power Guardians
In the manga only, the Sailor Power Guardians look like sprites— tiny versions of the Guardian and Outer Sailor Senshi who live in their respective castles. The series shows only the Guardian and Outer Senshi as having Power Guardians, and although all eight are shown, only three of them are referred to by name: Guardian Uranus, Guardian Neptune and Guardian Pluto. The rest of their names appear in cast drawing in one of the art books. The Sailor Power Guardians are responsible for keeping the Castles safe while the Senshi are on Earth, and provide some of the Senshi with their Sailor Crystals during the Dream arc.
Each Power Guardian communicates with her respective Senshi by calling on the power of that Senshi's Sailor Crystal. The Power Guardians can help the Sailor Princesses call on the power of their Castles to produce a new transformation. Thus they upgraded to new forms and poured this great, holy power into the Rainbow Moon Chalice, which in turn allowed Usagi to evolve into Eternal Sailor Moon for the first time.
The Sailor Power Guardians disappear in the Stars arc around the time of the killing of the Senshi they protect. The exact nature of their fate remains unclear, although the Senshi themselves later undergo rebirth.
The Silver Crystal
Main article: Silver Crystal
In Western myths and legends, silver has long been associated with the moon and femininity, especially after the 1500's and the alchemists. It was the alchemists who assigned the traits we are most familiar with in astrology to the planets. In many world mythologies, Greek, Roman, Indian, and some Native American, silver is the second age of man, coming after gold. Humans are not as peaceful, and life is slightly harder than the age of gold.
According to Hesiod, there are five ages of man: gold, silver, bronze, age of heroes, and iron, which is the age we are in now, and each age gets progressively worse. It is fitting considering the characters, that the "golden" age was called the Silver Millennium, but Naoko Takeuchi is a little off in her construction.
- Serenity’s Palace very closely resembles the architecture of the old Moon Kingdom.
- The manga reveals that the Crystal Palace is home to one of largest libraries in the world; the majority of the information is stored on microchips.
- The manga implies that the restored Moon Kingdom is part of Crystal Tokyo; Neo-Queen Serenity is shown telling Chibiusa that she will be taking lessons at one of the Moon’s castles, suggesting that the Moon Kingdom is still in use (as it was restored at the end of the first arc)
- The English dub states that the Moon Kingdom existed one thousand years ago, but the original manga made it prehistoric.