Church Slavonic is the conservative Slavic liturgical language used by the Orthodox Church in Eastern European countries including Bulgaria, Russia, Serbia, Ukraine, Poland, Croatia, and the Czech Republic.
In the archives of Museum of the Bible is the first complete Orthodox Bible printed in Church Slavonic. The Ostrog Bible was created in 1581. Prince Konstantin of Ostrog was a valiant protector of the Eastern Orthodox Church, ruling over an area largely dominated by Catholicism. He commissioned Ivan Fyodorov to establish a printing press in Ostrog to print the Bible in Church Slavonic.
The Ostrog Bible contains 76 books, including books accepted as canon in the Eastern Orthodox Church but considered apocryphal in other traditions. In fact, the Ostrog Bible has a unique canon.