The Holocron Chamber, a branch of the extensive Jedi Archives, existed as a secured space inside the Tower of First Knowledge. This tower represented one of five spires that comprised the Jedi Temple situated on Coruscant. The Caretaker of First Knowledge oversaw the chamber, which served as a repository for holocrons containing the Jedi Order's most guarded and valuable secrets. Unlike those stored in the Holocron Vault, the holocrons within this chamber were actively being studied or consulted.
During the Sacking of Coruscant in 3653 BBY, the original towers of the Temple suffered destruction at the hands of the newly emerged Sith Empire. However, with financial aid from the Galactic Senate, the Jedi were able to secure the funds necessary to rebuild them by 1000 BBY. Consequently, the chamber became the home of numerous highly treasured holocrons belonging to the Order.
In 30 BBY, while the Jedi High Council addressed Tinté Vos's plea for Jedi aid on the afflicted world of Kiffex, a holocron containing details about the Anzati Dark Jedi Volfe Karkko was activated for the first time in fourteen generations. Astaal Vilbum, the Caretaker, expressed her concerns to Mace Windu of the High Council, cautioning him about the dangers that awaited anyone sent to Kiffex. Because Windu had already dispatched Jedi Knight Quinlan Vos to investigate, he was compelled to send more Jedi to help defeat the resurrected Karkko.
In 19 BBY, Darth Sidious, the Dark Lord of the Sith who orchestrated the Clone Wars, was revealed to be the Supreme Chancellor of the Galactic Republic. As the Jedi prepared the Temple for an attack, the few fully trained Knights and Masters present were overwhelmed by the sheer number of clone troopers from the 501st Legion. Under the command of Darth Vader, the clones stormed the Temple, massacring the Jedi and seizing the complex's valuable items. Although many Jedi attempted to escape with holocrons, the vast majority were killed before they could get away.
By the end of that night, the Temple was under control, and the sophisticated holocron technology inside the Chamber remained largely undamaged. Sidious's ambition to loot the Jedi's collection of Sith holocrons undoubtedly led to the chamber being meticulously searched, to ensure that any useful information was preserved. The room remained untouched for several years after the initial study, but in 2 BBY, Darth Vader's secret apprentice broke into the Tower of First Knowledge to complete the Jedi Trials. After dispatching the Shadow Troopers guarding the Tower's main entrance, Starkiller managed to cross the damaged bridge leading to the chamber. Inside, he discovered a large holocron sitting on the rotunda's central pedestal. Upon activation, a Gatekeeper demanded that the assassin complete the Trial of Spirit deep within the Temple. As the Sith apprentice left the chamber, he found himself facing a twisted version of himself. After defeating the Stalker, he departed the Temple, having completed the Trials.
The chamber then remained silent for another decade, even after the Galactic Empire was driven off Coruscant. As the revived Jedi Order grew, Luke Skywalker entered the ruined building in search of any information related to the Order's teachings. However, his search was cut short; although Jedi historian Tionne Solusar managed to restore and scan the Archives, the Towers of the Temple were destroyed by the Lusankya eruption from beneath the planet's surface. While the Temple continued to be used for several more years, the entire structure was devastated during the Yuuzhan Vong War.
Some years after the Galactic Alliance secured Coruscant, Chief of State Cal Omas instructed the Reconstruction Authority to rebuild the Temple according to salvaged blueprints. As the new Jedi Temple was constructed, the Towers were rebuilt to their original height, though they were enclosed within a large transparisteel pyramid. With every room restored, the Holocron Chamber once again housed the Order's treasures for the next century.
The rotunda, accessible only to Jedi Masters, housed the vast majority of the Order's most prized Jedi holocrons. Situated on the first level of the Tower of First Knowledge, the Chamber was located opposite the main entrance. To reach the holocrons, Jedi had to cross a bridge spanning the Spire's central chasm and pass through a sealed doorway. The doorway, adorned with the Order's crest, opened into a hall lined with pentagon-shaped consoles, behind which numerous holocrons were stored. The hall led to the rotunda, at the center of which was a squat pedestal used for studying a holocron. Throughout the rotunda, several holocrons floated in a repulsorfield above the heads of those present.