1963
Students, radical Catholics and urban intellectuals inspired by the Cuban revolution founded the ELN.
1988
January-December: The ELN carried out approximately 50 bombings against the 500-mile Cano-Limon pipeline, causing extensive damage.
1990s
The ELN carried out numerous operations, including kidnappings, infrastructure attacks and armed attacks against military and law enforcement personnel. Notable events included:
In 1992, the ELN initiated peace talks, which were largely unsuccessful, with the Colombian government.
On May 31, 1995, seven ELN militants kidnapped a U.S. citizen and three Colombians at a Zaragoza gold mine. The Colombian army staged a rescue operation that left one hostage and two guerrillas dead.
In 1997, the U.S. State Dept. designated ELN as a foreign terrorist organization.
On July 22, 1998, a group calling itself the Popular Liberation Forces claimed responsibility for a series of 12 bombings in Medellin. The group said it was working with urban cells of the ELN.
On April 13, 1999, ELN rebels hijacked a Colombian Avianca airliner with 46 passengers and crew aboard.
2000
March 22: The Colombian government blamed the ELN for attacks on the national power grid that left the country without electricity for seven hours.
Sept. 17: The ELN was blamed for kidnapping 30 to 35 people at three separate road blocks near Cali. In November, the ELN released all the hostages as part of a cease-fire agreement with the Colombian government.
The ELN bombed the Cano-Limon pipeline at least 166 times in the course of the year.
2002
January: Representatives from the ELN, United Nations and the Colombian government began peace talks in Havana, Cuba. The government initially offered the ELN a 1,860 square-mile demilitarized zone in northern Colombia as a sanctuary.
June: After several months of negotiating, the Havana peace talks collapsed.
2003
January: The U.S. dispatched 60 special operations personnel to aid in security operations along the Cano-Limon pipeline in Arauca state, a favorite target of the ELN. They joined 10 special operations troops previously deployed to the region.
April 27: ELN rebels executed a young teacher in Medellin. She was kidnapped the week before and her father was told that she would be executed if he did not kill a right-wing paramilitary living in the neighboring town of Cocorna. The father refused, and the guerrillas killed the teacher.
Nov. 21: The ELN said it would release two of seven foreigners who were abducted in September in the Sierra Nevada Mountains of Colombia.
2004
June: Peace talks were restarted between Bogota and the ELN under the auspices of the Mexican government.
August: Colombia's government sent a cease-fire proposition to the ELN after the rebel group requested to negotiate through a Mexican mediator.
Nov. 17: ELN members killed nine police officers and injured three in an ambush in the northwest Choco province. About 100 members of the Cimarron front participated in the attack on the police patrol.
Dec. 11: Colombian troops captured Ramiro Velez, allegedly a member of the ELN's national directorate and the director of all ELN terrorist activity in southwest Colombia. Velez is blamed for the 1999 abduction of 180 worshippers from a Catholic church in Cali.
2005
April 4: The ELN announced it would not stop kidnappings, rejecting one of Bogota's preconditions for peace talks.
July 14: Government troops clashed with ELN fighters in the southwest Valle province, leaving at least 15 ELN members dead. The death toll was the largest for the ELN in more than three years.
Sept. 12: Bogota agreed to release ELN leader Francisco Galan from prison for three months to allow him to facilitate peace negotiations with the government. Galan had been imprisoned since 1992.
December: Bogota began exploratory talks as a precursor with the ELN in Havana, Cuba.
2006
March 23: The ELN handed over a Colombian soldier it had kidnapped on February 25 to representatives of the International Committee of the Red Cross. The group claimed the release was a sign of its willingness to negotiate.
April 25: ELN and government representatives began a new round of talks. After three days, they agreed to continue with the peace process.
June: Accusing the ELN of "attacks that we only expected from the enemy," the FARC publicly quarreled with the ELN, vowing to "punish those responsible."
October: Another round of formal talks was fruitless.
November: Four civilians were kidnapped by suspected ELN militants and one was subsequently killed. Around 600 civilians were also displaced by fighting between FARC and the ELN.
2007
January: Seventy families were displaced by battles between FARC and ELN.
March 21: Six civilians were wounded in a land-mine attack blamed on the ELN.
June: Four Colombian soldiers were killed and four more wounded after an ELN ambush in the village of Anori. Seven ELN members were killed; a weapons cache, including antipersonnel mines, was recovered.
July 25: Another round of peace talks ended without progress. Both sides agreed to resume negotiations in August.
August 30: A round of peace talks in Havana, Cuba, ended without agreement.
September: ELN leaders met with Venezuelan and Colombian officials in Caracas, Venezuela. Following the September meeting, ELN and Colombian leaders promised to renew peace talks in December 2007. Those talks did not take place.
2008
January: A Red Cross vehicle set off an ELN mine in La Llanadas municipality. The vehicle was damaged, but there were no casualties.
Jan. 7: Carlos Marin, alias "Pablito," was captured by the Colombian military. Pablito is adamantly opposed to peace talks with the government and led ELN's radical wing against such negotiations.
February: The ELN began restricting access to areas under its control in Samaniego in Narino province by laying antipersonnel mines at night and removing them during the day. When the military entered in the area, the rebels stopped removing the mines during the day.
March: Three civilians died and 11 others were injured by ELN mines during this month, according to the Colombian Ministry of Defense. Five government deminers were also wounded clearing the mines.
April 3: A meeting took place between ELN spokesman Francisco Galan and Colombian President Alvaro Uribe. Galan said ELN would return to the negotiating table. However, the group released a statement saying it did not share Galan's views.
May 26: ELN published a letter on its Web site seeking cooperation with the FARC.
July 14: The Colombian military rescued five ELN hostages in the northwestern province of Antioquia, killing at least five guerrillas.
December: A U.S. federal grand jury indicted ELN leader Pablito for two separate hostage incidents involving U.S. citizens in 1999 and 2003.
December: According to a Defense Ministry report, 383 ELN guerillas surrendered to the government in 2008.
Dec. 5: Nine policemen were killed in an ELN ambush in Arauca province.