In 1997, producer David Heyman searched for a children's book that could be adapted into a well-received film. He had planned to produce Diana Wynne Jones' novel "The Ogre Downstairs", but his plans fell through. His staff at Heyday Films then suggested "Harry Potter and the Philosopher's Stone", which his assistant believed was "a cool idea." Heyman pitched the idea to Warner Bros. and in 1999, Rowling sold the company the rights to the first four "Harry Potter" books for a reported £1million. A demand Rowling made was for Heyman to keep the cast strictly British and Irish; the latter's case has Richard Harris as Dumbledore and Fiona Shaw as Petunia Dursley, and not to cast foreign actors unless absolutely necessary, like casting of French and Eastern European actors in "Harry Potter and the Goblet of Fire" where characters from the book are specified as such. Rowling was hesitant to sell the rights because she "didn't want to give them control over the rest of the story" by selling the rights to the characters, which would have enabled Warner Bros. to make non-author-written sequels.