Oktar had been tried with 17 other defendants in an Istanbul court. The verdict and sentence came after a previous trial that began in 2000 after Oktar, along with 50 members of his foundation, was arrested in 1999.
In that court case, Oktar had been charged with using threats for personal benefit and creating an organization with the intent to commit a crime. The charges were dropped but another court picked them up resulting in the latest case.
Oktar planned to appeal the sentence, a BAV [Turkish acronym for Oktar's Science Research Foundation] spokeswoman said. No further details were immediately available.
Oktar, born in 1956, is the driving force behind a richly funded movement based in Turkey that champions creationism, the belief that God literally created the world in six days as told in the Bible and the Koran.
Istanbul-based Oktar, who writes under the pen name Harun Yahya, has created waves in the past few years by sending out thousands of unsolicited texts advocating Islamic creationism to schools in several European countries.
I've heard that many of "Harun Yahya"'s works are contain plagiarized bits of translations of books and articles from the Institute for Creation Research, minus the arguments for a young earth.
Another creationist currently in prison is young-earth creationist Kent Hovind, convicted for tax evasion.
According to Adnan Oktar's Wikipedia page, he was a former student of Edip Yuksel, a promoter of the works of Muslim imam Rashad Khalifa, who was murdered in Tucson, Arizona in 1990 by Islamic radicals. (One Islamic radical allegedly involved was Wadih el-Hage, a former Tucson resident who was Osama bin Laden's secretary in Sudan.) I met Yuksel at the University of Arizona, when he attended some of the same philosophy classes I did, and he gave me some pamphlets which touted Khalifa's claim that the Koran is demonstrably the word of God on the basis of numeric codes (similar to the Bible Codes), specifically involving multiples of 19.
The websites of Edip Yuksel criticizing Oktar are the reason why Wordpress.com is blocked in Turkey, as the result of a legal action by Oktar in that country. Yuksel describes his relationship with Oktar here.