"The pen ink then just dripped down the painting... They were really shocked when they came and saw what he had done."
A man wrote "a potential piece of yellowism" on Rothko's "Black on Maroon." I'm not going to dignify yellowism by linking to any manifestos.
ADDED: "A Russian artist who claims to have defaced a Mark Rothko mural in the Tate Modern gallery says he has engaged in a piece of art and improved the value of the multimillion-pound work...."
"I believe that if someone restores the [Rothko] piece and removes my signature the value of the piece would be lower but after a few years the value will go higher because of what I did," he said...
"I didn't destroy the picture. I did not steal anything. There was a lot of stuff like this before. Marcel Duchamp signed things that were not made by him, or even Damien Hirst."
He said that he admired Rothko, describing him as one of the great figures in art of the last century, but added: "I don't believe that what I have done is criminal. If the police are going to arrest me, then they are going to arrest me. I am OK with that."