The ISS Enterprise (ICC-1701) was a Constitution-class starship in the 23rd century serving the Terran Empire. The mirror Starfleet's ISS Enterprise is almost identical in configuration to a Federation Constitution-class heavy cruiser of the 2260s, and bears the same registry, NCC-1701, as the USS Enterprise. However, many minute details distinguished it such as the dagger emblem of the Terran Empire painted on the doors, and the posting of armed soldiers in the corridors.
The Enterprise was commanded by Christopher Pike until he was assassinated by James T. Kirk using an alien device known as the Tantalus field. The Enterprise participated in the quelling of the Gorlan uprising, and in 2267 was ordered to destroy the Halkan civilization.
In early 2267 the Enterprise visited Argelius II where chief engineer Montgomery Scott was suspected of several murders, however, Kirk protected his engineer from the authorities there and the ship departed. In 2267, Spock became the new captain of the Enterprise after James T. Kirk was promoted to Admiral.
In 2268, the Enterprise carried several Imperial Ambassadors to Babel where, in a shocking move, Coridan joined the Terran Empire through diplomatic methods as opposed to the expected invasion and occupation. Later that year, the Enterprise successfully captured and towed a Romulan bird-of-prey to Starbase 10. The Enterprise later took part in the testing of the M-5 computer testing during which a 'malfunction' caused the ISS Excalibur to fire upon the Enterprise damaging it; the incident was later believed to be a trap set by Grand Admiral Garth to assassinate Spock. Later, the Enterprise was ambushed by Garth himself at Elba II in another unsuccessful attempt to kill Spock and his crew.
The Enterprise underwent a significant refit in 2270 altering nearly every aspect of the ship. In 2270, Enterprise was named flagship of the Empire after Admiral Kirk ascended to the rank of Grand Admiral after murdering Grand Admiral Matthew Decker, foiling a plot by the Empress to have him killed.