British-Indian novelist Salman Rushdie and British musician Cat Stevens, who later changed his name to Yusuf Islam, began their long-running conflict in 1989, when Stevens made statements that were somewhat supportive of Iranian leader Ayatollah Ruhollah Khomenei's fatwa calling for Rushdie's death. While the exact nature of Stevens' comments has been disputed ever since, there's no question that it began a still-running and extremely bitter war of words between the two men.

The conflict reignited most recently when a reporter asked Rushdie for his thoughts on Stevens's performance at the Washington, D.C., rally held by Jon Stewart and Steven Colbert. The author responded, "I've always liked Stewart and Colbert but what on earth was Cat Yusuf Stevens Islam doing on that stage? If he’s a 'good Muslim' like Kareem Abdul-Jabbar then I’m the Great Pumpkin. Happy Halloween."

So what, exactly, is the nature of the Twenty Years War between these two figures? Well, it's long and confusing and involved. Fortunately Stanford literary blogger Cynthia Haven has chronicled the entire thing, including a bizarre and apparently ongoing side-conflict involving YouTube videos and copyright complaints. You'll have to read her accounting if you want to try and figure it out.

Haven also has a follow-up reporting more of Rushdie's unhappiness with the Stevens rally appearance. He tells another Stanford blogger, "I spoke to Jon Stewart about Yusuf Islam’s appearance. He said he was sorry it upset me, but really, it was plain that he was fine with it. Depressing." Havens concludes by lamenting the state of free speech, although it's not clear if she's criticizing Rushdie's objection that Stevens would appear at the rally or Stevens's possible support for killing Rushdie.