Update to this story:

ISTANBUL (Reuters) — An internationally acclaimed Turkish classicalpianist is to stand trial on charges of insulting Muslim religious values in comments posted on Twitter, an Istanbul court ruled on Friday.

Fazil Say has performed with the New York Philharmonic, Berliner Symphoniker, Israel Philharmonic, Orchestre National de France and Tokyo Symphony Orchetra and has served as a cultural ambassador to the European Union.

The 42-year-old pianist quoted a well-known poem by the 11th Century Persian poet Omar Khayyam that ridiculed the hypocrisy of people who pretend to be pious.

State-run Anatolian news agency reported that the court “accepted an indictment against Say for allegations of explicitly insulting religious values.” If convicted, the pianist could face 18 months in prison.

Religious conservatives in mostly Muslim Turkey have become more assertive since Prime Minister Tayyip Erdogan’s Justice and Development Party (AKP) swept to power a decade ago, arousing fears among opponents that the republic’s secular traditions are being eroded.

Khayyam’s poem is in the form of a questions to believers: “You say rivers of wine flow in heaven, is heaven a tavern to you? You say two houris await each believer there, is heaven a brothel to you?”