In the 2380s, the cube encountered two Tal Shiar vessels. While one ship was spared, the second, the scout ship Shaenor on which Ramdha was a passenger was assimilated; the only Romulans ever assimilated by the cube. The sheer force of Ramdha's despair, caused by her prior contact with the Admonition, triggered a submatrix collapse on the cube that immediately severed it from the Collective. (PIC: "The End is the Beginning", "Broken Pieces")
Romulan Reclamation Site
Afterward, the Romulan Reclamation Site was established within the cube. It was controlled by the Romulan Free State, who captured the cube and profited from the exploitation of Borg technology. Through treaty with the Federation, both governments worked there as guests of the Borg Artifact Research Institute. All technology and drones aboard the vessel had been rendered inactive, although researchers were warned to take special measures when entering the gray zone. (PIC: "Maps and Legends")
The cube had either been damaged or modified while under the control of the Romulans as large sections of the outer hull had been replaced by force fields to maintain the ship's structural integrity. (PIC: "Remembrance") The interior of the cube had also been modified to allow for living quarters, not commonly found on Borg vessels. (PIC: "Remembrance"; TNG: "Q Who")
Also operating on the cube was the Borg Reclamation Project, which was independent by treaty. Because of this, the Romulans had to allow Federation diplomatic envoys to the project if the director agreed to this. By the year 2399, the project was under the direction of Hugh, who was stationed aboard the Artifact. (PIC: "Maps and Legends", "The Impossible Box")
The Artifact contained a room called a queencell possessing a spatial trajector device that Admiral Jean-Luc Picard and Doctor Soji Asha used to transport to the planet Nepenthe in secret. Following their escape, Tal Shiar/Zhat Vash Colonel Narissa commenced a genocide of the xB population of the Artifact in retribution for Director Hugh's assistance to Picard. During this attack, Seven of Nine took command of the Artifact, initiated automated repairs to it and reactivated the Borg population which was immediately decimated by ejection into space from a massive fissure opened by Narissa. After the Romulan evacuation, Seven of Nine relinquished control of the Artifact and the cube remained active with a reduced population. (PIC: "Broken Pieces")
While Seven was connected to the Artifact, she sensed that Picard and La Sirena were in danger. Thus, she took the cube through a transwarp conduit to Coppelius to assist. Shortly after, the Artifact's power was disabled by orchids, causing it to crash on the planet's surface. (PIC: "Et in Arcadia Ego, Part 1", "Et in Arcadia Ego, Part 2")
A piece of promotional artwork depicting "The Artifact" was published on Facebook, following the release of "Maps and Legends".
In the Star Trek: Voyager episode "Timeless", set in 2390 of an alternate timeline, Harry Kim mentioned a wrecked Borg cube in the Beta Quadrant. In an Instagram story dated 5 March 2020, when asked if the Artifact was the same cube, Michael Chabon responded: "Do you have a theory?"