The Associated Press reports that he'd been hospitalized since March 12 in Yangon with respiratory problems. The cause of death was organ failure.
Win Tin founded the National League for Democracy in 1988 along with opposition leader Aung San Suu Kyi. They were both arrested the following year. Suu Kyi was placed under house arrest. Win Tin was sent to prison. His sentence, which was extended twice, totaled 21 years, of which he served 19. Much of his time in prison was under harsh conditions. The Los Angeles Times reports:
"Win Tin was jailed in 1989 and harshly treated — tortured, denied medical treatment and kept in solitary confinement. He would later recount in a memoir how his jailers refused him pen and paper, so he ground up bits of brick into a paste that he used to write poetry on the walls of his cell."
A spokesman for the NLD called him a "great pillar of strength."
Win Tin was freed in 2008, along with hundreds of other prisoners, as part of a general amnesty by Myanmar's ruling junta. Still, he continued to wear his blue prison shirt as a mark of solidarity with other political prisoners in the country. He also continued working with the NLD until Myanmar transitioned to an elected government in 2011 (though as the AP notes, the government is still dominated by the army).
Win Tin was a close ally of Suu Kyi, who won the Nobel Peace Prize in 1991, but was critical of her in recent years for what he saw as her conciliatory relationship with Myanmar's military leaders. As Reuters reports, "He publicly disagreed over her decision to run in April 2012 by-elections that took the NLD into parliament, arguing that the party's participation lent authority to a government packed with former generals." Still, he praised Suu Kyi's commitment to democracy.
He told Reuters in 2010 that he "was cut out to be a journalist rather than a politician." The news agency said a funeral is to be held Wednesday.