The Galactic Clone Wars were a series of significant conflicts that stretched across the whole galaxy, and were widely regarded by most people as the worst conflict in the history of the galaxy. The Clone Wars were brought about by the spreading conflict of the Mandalorian Civil War and the cloned Mandalorian mercenaries used by the Mandalorian Death Watch. The spreading Mandalorian War caused many governments and organisations to become unsettled and question whether the Republic would have the military force to defend them should the Mandalorian conflict spill into their systems. When both military and financial revisions failed to pass through the Galactic Senate, several of the more powerful corporate entities simply withdrew from the Republic, choosing to create their own defensive armed forces. These corporations were led and united by the chairman of the InterGalactic Banking Clan, San Hill, into a cohesive Commonwealth of Independant Systems, secretly manipulating events as the Sith Lord Darth Plagueis. The Galactic Republic considered such an act to be against the various constitutions and laws that the corporations had agreed to upon joining the Republic, and chose not to officially recognise the independance of the Separatist groups.
However, many planets realised that the Commonwealth of Independant Systems possessed enough resources to supply sufficient armed defences to each system within its control, as well as provide numerous financial benefits to these systems. In 55 BBY, after the Battle of New Cov and subsequent aiding and razing by the Mandalorian Death Watch, several thousand systems seceded from the Republic, causing the beginning of the Separatist Crisis. San Hill declared a need for the increasingly vocal Commonwealth to consolidate its military power, so that the Republic would listen to its requests. In secret, this was a plan to create a military force powerful enough to trigger a galactic war with the Republic and allow Sith control to descend across the galaxy. As San Hill, Plagueis commisioned the growth of a clone army, using the various illegal cloning facilities that existed throughout the Outer Rim and more noticably prevalent throughout the Rishi Maze, which was almost entirely ignored by the Galactic Republic. Plagueis had actually been growing elite clone soldiers for almost a decade prior to the beginning of the Separatist Crisis, and was the person who had provided the Death Watch with Mandalorian clone mercenaries.
In 52 BBY the Republic dispatched several groups of emissaries and diplomats to the Commonwealth to increase the strength of the negotiations that had taken place over the past three years. One such group of diplomats, including the Jedi Master Qui-Gon Jinn and his Padawan Obi-Wan Kenobi, was dispatched all the way to the Rishi Maze, to negotiate with and investigate the InterGalactic Banking Clan. When negotiations went sour the true intentions of the small group, to investigate the Separatists, was uncovered and San Hill ordered that they be executed. The diplomats and emissaries were killed by San Hill's bodyguards, but the two Jedi managed to escape and discovered that the planet was honeycombed with underground facilities, which all held clones either in stasis or in varying stages of growth. The facilities also contained training units and flash-imprinting machinery, and data on the total collected army of the Commonwealth. Jinn was able to obtain a copy of this data and escape from Kesilggar with Kenobi, bringing his findings back to the Galactic Senate.
Examination of the data indicated that the Separatists had built up a military force of almost 200 quadrillion clones of varying types over the past decade, causing great alarm within the Senate. Due to the hostile actions of the Separatists on Kesilggar and the discovery of the secret army, the the Republic responded by conscripting the various indigenous militaries, police and security forces of the systems it still possessed, as well as the prowess of the Jedi Order, and declared war on the Commonwealth of Independant Systems, determined not to allow such a militarily and economically powerful group become independant and exempt from laws and restrictions. The galactic media and news feeds would refer to this act as the beginning of the Galactic Clone Wars.
The Clone Wars started out as a series of brush-fire conflicts in unimportant regions of space, but as the Separatists continued to produce and unfreeze more clones and provide supplementary droid forces to crew ships and augment their ground forces, the Republic continued to draw on more indigenous military forces, as well as beginning their own clone soldier program, utilising facilities providedd by Spaarti Creations. The wars would end up lasting over 33 years, with the Separatists coming to rely ever more on their droid armies as the Republic captured and destroyed various cloning facilities.
In 19 BBY the Republic finally claimed victory over the Seperatists, but the ramifications of the wars were significant. The death toll was the largest ever seen in any single period of conflict in the galaxy, many planets entered periods of financial and social crisis, and the Galactic Republic was dissolved to allow the introduction of the Galactic Empire under the rule of Emperor Decarte Palpatine. In fact, this had been the secret intention of the Clone Wars all along, as a reason to seize control of the galaxy under the rule of Palpatine, secretly a Dark Lord of the Sith.