This page contains information regarding Star Trek: Picard, and thus may contain spoilers.
In the 2380s, the cube encountered two Tal Shiar vessels. It assimilated the scout ship Shaenor, on which Ramdha was a passenger. 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")
Afterward, the Romulan Reclamation Site was established within the cube. It was controlled by the Romulan Free State, who profited from the exploitation of Borg technology. Romulans and non-Romulans 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")
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. (PIC: "Maps and Legends", "The Impossible Box")
The Artifact contained a room called a queencell possessing a spatial trajector device that Jean-Luc Picard and Soji Asha used to transport to the planet Nepenthe in secret. Following their escape, the Romulan Zhat Vash agent known to the Federation as Narissa Rizzo 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 Rizzo. 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. Upon the Romulan attack, it escaped. (PIC: "Et in Arcadia Ego, Part 1", "Et in Arcadia Ego, Part 2")