The Sudan People's Liberation Army (SPLA) was formed in 1983 to oppose the implementation of shari'a law, or strict Islamic law, by Sudanese President Nimeiri.  While the largely Muslim population of Sudan's Northern provinces generally welcomed the change, the Christians and Animists of southern Sudan were alarmed.  According to the treaty that had ended the country's first civil war in 1972, the South was to maintain its autonomy from the North.  Nimeiri's attempt to implement shari'a nation-wide violated that agreement and created widespread resentment among the Southern population.  Sent by the Army to quell a mutiny in the South, Lt. Col. John Garang instead embraced the insurrection and became its leader, forming the SPLA.  From an initial nucleus of 500 soldiers in 1983, Garang's rebel army grew rapidly, hitting an estimated 50,000 to 60,000 by 1991.  The group's stated goal is the formation of a secular, democratic Sudan.  In the mid-nineties, the SPLA became the vanguard element of a rebel umbrella organization, the National Democratic Alliance, which even contained some moderate Muslim parties.  The SPLA's success, however, cost the citizens of Sudan dearly.  It is estimated that the civil war, which did not cease until 2002, took some 1.5 million lives.  <P> Although the SPLA was primarily designed to perform military operations against the Sudanese Army, it also engaged in a few acts of terrorism against westerners and western interests in the country.  In 1999, the SPLA took six Red Cross workers hostage, four of whom died in captivity.  Although SPLA spokespeople claim that the deaths occurred during a botched rescue attempt, the Sudanese government claims that they were executed.  Two years later, the SPLA claimed responsibility for one successful bombing and one unsuccessful bombing attempt against oil companies operating in Southern Sudan.  The SPLA specifically targeted the oil industry to prevent oil proceeds from strengthening the government forces.  In 2002 the Khartoum government and the rebels were able to hammer out a power-sharing agreement that has ended, or at least significantly lowered the ferocity of, Sudan's civil war.  As part of the implementation of this agreement, John Garang was named Vice-President of Sudan in 2004.