In 1979, DC and Marvel agreed to co-publish a crossover series involving the two teams, to be written by Gerry Conway and drawn by George Pérez. The plot of the original crossover was a time travel story involving Marvel's Kang the Conqueror and DC's Lord of Time. Writer/editor Roy Thomas was hired to script the book, based on Conway's plot, and although work had begun on the series in 1981 (Pérez had penciled 21 pages by mid-1983) and it was scheduled for publication in May 1983, editorial disputes - reportedly instigated by Marvel Editor-In-Chief Jim Shooter - prevented the story from being completed. The failure of the JLA/Avengers book also caused the cancellation of a planned sequel to the 1982 The Uncanny X-Men and The New Teen Titans crossover.