ISTANBUL — A court here on Friday charged Fazil Say, a classical and jazz pianist with an international career, with insulting Islamic values in Twitter messages, the latest in a series of legal actions against Turkish artists, writers and intellectuals for statements they have made about religion and Turkish national identity.
Mr. Say, 42, who is also a composer, is accused of “publicly insulting religious values that are adopted by a part of the nation,” the semiofficial Anatolian news agency said. A trial is scheduled to begin on Oct. 18, with Mr. Say facing up to 18 months in prison if convicted.
It is unusual for Twitter posts to be the subject of an indictment in Turkey. Some of the messages were written by Mr. Say, but one, which poked fun at an Islamic vision of the afterlife, was written by someone else and passed along by Mr. Say via his Twitter account. Likening heaven’s promise of rivers of wine to a tavern and of virgins to a brothel, it referred to a poem by the 11th-century Persian poet Omar Khayyam, Mr. Say said in a text message from Slovenia, where he had just arrived for a concert.
Another Twitter post, this one written by Mr. Say, joked about a muezzin’s rapid delivery of the call to prayer, asking if he wanted to get away quickly for a drink. The messages are no longer available online. The pianist, who has frequently criticized the pro-Islamic Justice and Development Party government over its cultural and social policies, publicly defines himself as an atheist — a controversial admission in Turkey, which is overwhelmingly Muslim.
In his text message from Slovenia, Mr. Say said he was only one of 165 people who shared the Twitter post on the vision of Islamic paradise.
“I just thought it was a funny allegory and retweeted the message,” he said. “It is unbelievable that it was made into a court case.”
He continued, “This case, which goes against universal human rights and laws, is saddening not only when judged on its own merit but also for Turkey’s image.”
Many intellectuals and writers have faced similar charges in recent years, including Orhan Pamuk, the Nobel laureate, who last year was fined $3,700 for saying in a Swiss newspaper that Turks “have killed 30,000 Kurds and 1 million Armenians.”
The European Union, which Turkey is seeking to join, and other international organizations have criticized such actions as violations of free speech.
Mr. Say, who has served as a European Union culture ambassador, has a busy international career, with frequent engagements in Europe and to a lesser extent in Asia and the United States. He has performed with major orchestras, including the New York Philharmonic and the Berlin Symphony Orchestra.
Mr. Say is also known in music circles for his eccentricities during performances, like conducting phrases with a free hand, giving range to facial expressions and humming along.
His last recital in New York was in April, at the Metropolitan Museum of Art, in connection with the opening of the New Galleries for the Art of the Arab Lands, Turkey, Iran, Central Asia and Later South Asia.
Anthony Tommasini, in reviewing the concert for The New York Times, said Mr. Say drew a “large and enthusiastic audience.” Of his performance of Leos Janacek’s Sonata “1.X.1905,” Mr. Tommasini wrote, “Mr. Say brought improvisatory freedom and vivid colorings to this harmonically misty, elegiac and restless music.”