The Old Republic
The Old Republic was the Republic of legend, greater than distance or time. Before a cruel and ruthless Empire supplanted it, the Old Republic was the democratic union that governed a galaxy for thousands of years. Those who lived in it knew it as the Galactic Republic, or more simply, the Republic. Justice and peace in the Republic was protected by the Jedi Knights. As the Republic grew more and more powerful, many of the bureaucrats and Senators that ran the government grew increasingly corrupt or complacent. Furthermore, partisan politics and personal agendas also hampered effective governing. Senator Palpatine was eventually elected Supreme Chancellor, which was only his secrect plan. A sepratist movement was led by Count Dooku, which broke apart the Republic. The Republic eventually crumbled and was rebuilt in the New Order.
The Rebel Alliance
Born shortly after Palpatine's transformation of the Old Republic into the New Order, the Alliance started as little more than a rag-tag group of freedom fighters woefully under-equipped to challenge an enemy as mighty as the Galactic Empire. The continued injustices of the Empire, however, brought many into the Rebellion's fold. The Rebel Alliance scored a major victory over the Empire by using stolen technical plans to formulate an attack strategy capable of destroying the Empire's most fearsome weapon: the Death Star. The Alliance suffered a set back on the ice planet of Hoth. But a year and half after that battle they were ready for another attack. This time successful, they destroyed the second Death Star and killed Palpatine as well as the Imperial Fleet scattering, thus ending the New Order oppression.