thirty years of feuding

The Literary Saloon posted a story about Gabriel Garcia Marquez and Mario Vargas Llosa ending a thirty year feud. Apparently they actually came to blows at a movie in Mexico in 1976.

Yeah.... i wanna know... what movie was playing?

Their political differences i was aware of. Vargas Llosa wrote a book about Garcia Marquez, and had it published in 1971. I've been searching for ten minutes, and not turned up why this happened.