Operation: CHARLEMAGNE

Operation: CHARLEMAGNE was a code name for the first major UNSC counterattack against the Insurrectionists on Eridanus II in the late 25th century. It marked the first tactical deployment conducted by the ORION Project. It was also the only occasion where an entire unit of SPARTAN-Is was deployed as a group.

Background
In June 2494, the rebel Colonel Robert Watts rallied the secessionist movements on Eridanus II, equipped by traitors within the Colonial Military Administration's command hierarchy. Watts orchestrated a methodical and thorough series of assaults involving terror bombings, political assassinations and kidnappings in order to seize control of the planet from the CAA-aligned Eridanus Government; the rebels were even able to gather a small fleet of warships through their CMA contacts. Watts' campaign had a significant impact on shipping to and from the planet, which prompted the Eridanus Government to call for the UNSC's aid in the December of 2494.

Operation
In response to the rebel attacks, the UNSC launched Operation: CHARLEMAGNE in January 2496. A large UNSC battle group was sent in to crush the rebel forces, which were defeated at the cost of four destroyers. Meanwhile, the group of ORION Project operatives (SPARTAN-Is) attacked the rebels in a swift and silent special operation that resulted in only one casualty on the ORIONs' side, and several crippling losses on the rebels' side. The Spartans recovered a sub-orbital transit station over the planet without ever being observed.

Operation: CHARLEMAGNE continued for over a year, and saw the first field use of the SP42 "Cobra" MBT by the UNSC Marine Corps in 2497.

Aftermath and legacy
While the rebellion was quelled, elements of the rebel forces escaped into the system's asteroid belt, remaining there for several decades. Under Watts' leadership, the Insurrectionists attempted to seize power again in 2513, leading to another clash between the UNSC and the secessionists in Operation: TREBUCHET.

The ORION supersoldiers' success in the operation is believed to have positively marked the ONI's propaganda machine, having sparked various conspiracy theories with regard to the operation's perpetrators within civilian and rebel circles.

Trivia
The operation was named after Charlemagne, the Frankish king who changed the face of Europe in the 8th and 9th centuries CE.