Caillte was first settled by the Mandalorian Neo-Crusaders in 3964 BBY, who built the outpost Unity beneath the planet's crust. The Mandalorian Feruun Lern became a dominant figure at the outpost and invited other Mandalorians there, to rediscover the warriors within themselves. Near to the end of the Mandalorian Wars, Lern and many of his followers left the planet, to participate in the Battle of Malachor V. The Madalorians were defeated during the battle and Lern and his followers returned to Unity, to find that, in their absence, the base had been stripped by some other Mandalorians. During the Jedi Civil War, Lern and his followers abandoned the base to join forces with Canderous Ordo.
In 405 BBY, the Corporate Sector Authority arrived on Caillte and established a scientific outpost there. During the construction of the outpost, they discovered the remains of the old Mandalorian settlement.