The Romulan Technocracy was the name of the mirror universe Romulan nation in the late 24th century mirror universe. A conflict with the Terran Empire had resulted in the devastation of Romulus earlier in the century; Romulan science saved Romulan society and created a state where scientists (technocrats) held power.
By contrast with the Romulan Star Empire in the Federation universe, the Technocracy was more advanced in diverse areas of science and technology, including cloning, genetics, cryonics, terraforming, transporter technology and starship construction. Using Romulan methods, the Alliance built their own version of a Quantum-class starship in record time, equipped with quantum slipstream drive. Romulan science was highly valued by other powers, including the Imperial Union of Planets. However, this was not enough to save Romulus from an Imperial invasion in late 2385. Whether the Technocracy survived the fall and integration of Romulus into the IUP has yet to be revealed. (Star Trek: New Empire)