BANGKOK (Reuters) - Thailand’s military court on Wednesday dropped the prosecution of an 85-year-old academic who had been accused of royal insult for questioning the truth of a 17th century elephant-back battle, he and his lawyer said.

Under Thailand’s strict lese majeste law against defaming, insulting or threatening the monarchy, Sualak Sivaraksa could have been jailed for up to 15 years if found guilty over the accusation, which related to a university seminar in 2014.

He had questioned whether a battle had really taken place in which Thai national hero King Naresuan the Great is said to have killed a Burmese prince. King Naresuan ruled from 1590 to 1650.

Thailand’s junta has made increasing use of the lese majeste law since seizing power in 2014 and the dismissal of the case before prosecution was a rarity.

Sulak gave thanks to King Maha Vajiralongkorn, who succeeded his revered late father, King Bhumibol Adulyadej, in 2016.

“I think this case has stopped because of the grace of the king. I asked many people for help and no one dared. So I petitioned the king,” Sulak told reporters at the court.

His lawyer, Puangtip Boonsanong, said the court had cited lack of evidence as the reason for dropping the case.

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Neither the court nor the police made any comment.

At least 94 people have been prosecuted for lese majeste and as many as 43 have been sentenced since the 2014 coup. Most of the others prosecuted are still facing trial.

The lese majeste law does not apply to past or deceased kings but is sometime loosely interpreted and used to defend the royal establishment.

In 2013, the Supreme Court sentenced a man to two years in prison over a comment he made in 2005 about King Mongkut, who reigned from 1851 to 1868, because it could have affected the then king.

King Naresuan’s elephant battle is highly celebrated in Thai official history and is commemorated each year by the military as the Royal Thai Armed Forces Day.

Despite being a self-proclaimed royalist, Sulak was arrested and charged with royal defamation against King Bhumibol in 1984 for criticizing the monarchy. The case was later withdrawn following international pressure.