The King represented the country in his travels abroad, meeting with foreign leaders. Over the decades, he worked to improve the lives of ordinary Thais through civic programs, drawing on his engineering background to advise on projects like new irrigation systems.
Strict laws, against criticizing the monarch restricted frank discussion of his life and personality. The lese majeste laws carry punishments of up to 15 years in prison, and ordinary Thai citizens, as well as the government, could bring charges on behalf of the King, so the laws were sometimes abused as a political weapon.
Human rights groups have criticized prison sentences handed down to people convicted of defaming or insulting the Thai royal family. Even the King appeared to question the restrictive climate.
"If the King can do no wrong, it is akin to looking down upon him, because the King is not being treated as a human being," he said in his 2005 birthday speech. "The King can do wrong."
But his words seemed to do little to deter the prosecutions. As the political situation in Thailand deteriorated in the wake of a military coup that ousted populist leader Thaksin Shinawatra in 2006, successive administrations pursued more lese majeste cases.
According to Human Rights Watch, between January 2006 and May 2011, more than 400 lese majeste cases were brought to trial. The number of prosecutions decreased after Prime Minister Yingluck Shinawatra, Thaksin's younger sister, took office in 2011, the rights group said.
Yingluck was herself ousted from power in a military coup in May 2014, in the two years that followed, Human Rights Watch said there were 68 lese majeste cases brought to trial, relating to opinions, poems, cartoons and online comments.
Analysts said the laws prevented public discussion in Thailand on what would happen after the King's death, deepening uncertainty and political tensions.
Young King