Why the Death Edict on Salman Rushdie?

The stabbing of Salman Rushdie raises the question: Why did Ayatollah Ruhollah Khomeini sentence Salman Rushdie to death in 1989 for his novel The Satanic Verses?
The stabbing of Salman Rushdie raises the question: Why did Ayatollah Ruhollah Khomeini sentence Salman Rushdie to death in 1989 for his novel The Satanic Verses?