Military prosecutors on Wednesday dropped lese majeste charges against 85-year-old historian and social critic Sulak Sivarasa brought over a comment he made about king Naresuan the Great more than three years ago.
Mr Sulak said after meeting the prosecutors at the Bangkok military court that the prosecutors dropped the two charges for lack of evidence.
He was earlier charged with lese majeste under Section 112 of the Criminal Code and with putting false information into a computer system.
Mr Sulak was charged by police in October last year for comments made during a history discussion at Thammasat University in Bangkok in 2014, when he cast doubt on the occurrence of a famed duel on elephant back over 400 years ago between king Naresuan and a Burmese prince.
Accepted history says the king and the prince fought on Jan 18, 1592, and Jan 18 is celebrated as Royal Thai Armed Forces Day.