The planet was first colonized in 1,989 BBY when Lord Ecclessis Figg first commissioned Cloud City, to be built by the Incom Corporation at the same time. The planet had its own Jedi Enclave.

In 22 BBY, the planet served as a refuge for children orphaned by the Clone Wars, but it was soon conquered by the Confederacy itself. It was a great loss for the entire Galactic Republic; the Confederacy had secured the Tibanna gas refineries that were the main source of energy for the Republic's turbolasers aboard capital ships.

The Millennium Falcon, by Han Solo's admission, just barely made it there from the Anoat system with only a back-up hyperdrive.

Lando Calrissian, the previous owner of the Millennium Falcon, served as Baron Administrator of Cloud City and provided well-paying jobs for the Ugnaughts until the Galactic Empire took over. The Imperial garrison was commanded by Captain Hugo Treece.
Bespin lifezone at sunset
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Bespin lifezone at sunset

When Han Solo along with Leia Organa, C-3PO, and Chewbacca came to Cloud City to escape from the Empire, they walked into a trap set up by Darth Vader, which Lando was forced into aiding. Han Solo was frozen into Carbonite and Leia Organa and Chewbacca were to remain in the city. As Boba Fett brought Han onto his ship, Slave I, Lando with Lobot's help, got the two out of Imperial controller along with blasted Threepio and tried to rescue Han from Fett but failed.

Meanwhile, Luke Skywalker dueled Vader, lost his right hand, and Vader revealed that he was Luke's father. Pinned between the choice of going with his long-lost father or dying by his blade, Luke plunged into a air vent. When he fell, he managed to grasp onto a weather vane beneath the city. In pain from his wound and his new knowledge, Luke pleaded for Obi-Wan's help, to no avail. He managed to telepathically communicate with Leia, and was recued by the Millennium Falcon. The Falcon in turn managed to escape from the Executor when R2-D2 fixed the disabled hyperdrive.

Lando would eventually return to being Baron Administrator. However, a garrision of troops was left on the planet. Lobot temporarily ousted the garrison from the planet by tricking them into thinking Cloud City's repulsorlift pods were compromised.
The Battle of Bespin.
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The Battle of Bespin.

Later, just before the Battle of Endor, the Alliance removed the renewed Imperial presence there by leading Rogue Squadron and the Rebel SpecForce against the Empire in the Battle of Bespin. The Rebel victory secured shipment of vital Tibanna to the Rebel cause.

Eventually, Lando lost the Cloud City to Zorba the Hutt in a game of sabacc. Later on, Lobot became administrator of the City, although it was briefly taken over by the Empire Reborn.

In 35 ABY, the planet was plagued with Tibanna tappers. Jaina Solo and Zekk were assigned to investigate. It was eventually discovered the stolen tibanna was being used for the Killik nest ships constructed in the Tusken's Eye.

In 40 ABY, along with Adumar, Commenor, Fondor and the Corporate Sector Authority, Bespin became allied with Corellia in an attempt to challenge the benefits of membership in the Galactic Alliance, during the Second Corellian Insurrection.