Simplify the following text for a Grade 9 native English-speaking person.
Original: The book , whose full title is Magnum crimen - pola vijeka klerikalizma u Hrvatskoj ( The Great Crime - a half-century of clericalism in Croatia ) , was written by a former Catholic priest and professor and historian at Belgrade University , Viktor Novak ( 1889 â `` 1977 ) .
Simplified: `` Magnum crimen : pola vijeka klerikalizma u Hrvatskoj '' ( i.e. Major accusation : Half a century of clericalism in Croatia ) is a book first published in Zagreb in 1948 . The book was written by a Croatian Roman Catholic priest , Dr. Viktor Novak ( 1889 - 1977 ) , who was also a professor at Belgrade and Zagreb Universities , and the member of the Yugoslav Academy Science and Arts . .