At some point in Ancient History, the Mondoshawan visted the Humans "before time was time". A succession of Priests were established to protect the Fifth Element and the Chamber in Egypt. Evil attempted to destroy the world 5000 years prior to the events of The Fifth Element, possibly multiple times - and perhaps even causing the Moon to form around Earth.
In The Divine Language, the word 'Mondoshawan' translates as 'guardians'.
In 1914, prior to the Outbreak of World War I, a Mondoshawan ship visited Earth, specifically the Chamber in Egypt. Upon arriving, the ship's crew were greeted by the current Priest who ensured them that the stones and Fifth Element were safe, despite an archaeologist and his apprentice investigating the chamber. After rendering the archaeologist unconscious, the Mondoshawan proceeded to extract the stones and Fifth Element. When the priest asked why the Mondoshawan were taking Earth's only defense against Evil, the Leader replied "War is coming, stones not safe on Earth anymore". The Leader (distinguished by the large spikes on his armour) was unfortunately shot at by the bewildered apprentice and was sealed in the chamber, but not before passing the Key to the Priest with the command "Pass the knowledge to the next priest as it was passed on to you". The Mondoshawan then left Earth, returning 300 years later.
Sol System, 2214
Returning with the Fifth Element as they had promised, the Mondoshawan made their way to Earth as the Great Evil returned. Unfortunately, Mangalores hired by Zorg shot down the Mondoshawan's ship as it passed Jupiter in a viscious attack that left only one survivor, the Fifth Element who was later retrieved by Human Scouts and reanimated back in New York, Earth.
Although only the Mondoshawan accompanying the Fifth Element and Elemental Stones were seen, it is assumed there are other Mondoshawan. The Mondoshawan are also excellent strategists and back-up planners. Although they failed to safely deliver the Fifth Element to Earth themselves, they did seperate the Fifth Element from the Elemental Stones, preventing the loss of them all.