The Clone Wars started with a sudden onslaught by the Imperial forces, supported by scattered bands of Republicans with Jedi assistance. Separatist systems began to fall quickly, and it seemed as if the war would soon be decided. But, with need to garrison friendly systems, occupy captured systems and assault enemy systems, the Imperial forces rapidly became stretched. As the smallest group of systems the Imperials had the most limited manpower, and their Republican allies, though more numerous, were unable to mobilise efficiently or quickly.

Just as the Imperial offensive began to run out of steam, the Separatists revealed their newly discovered cloning technology. Making use of simple, cheap, mass-produced weapons, armour, spaceships and clones, they overran the Imperial and Republican forces through sheer weight of numbers. They suffered enormous losses to their enemies better tactics and weapons, but were able to more than make good those losses.

By combining Imperial plans and technology with Republican manufacturing capacity, the Senatorial forces could build more quickly than the Separatists, but it wasn't until a Jedi espionage group were able to obtain cloning technology that they were able to stop the Separatist advance.

Soon fleets and armies of almost inconceivable sizes were clashing across the Galaxy. Imperial technology and tactics helped by elite Jedi lead Republican forces were eventually able to overcome the Separatist resistance and peace was restored to the Galaxy.

At the end of the Clones Wars there were Imperial Garrisons in most systems, either put there are for protection or occupation. This included most Separatist systems and many Republican. Backed by the power of the massive Imperial Fleet and supported by ground forces an almost every important system in the Galaxy, the Republican war leader betrayed both his Republican supporters and the Jedi when he declared himself Emperor and the Old Republic to be dead.

Next: The Empire