Leslie Epstein

Julius was eventually offered a writing job at Warner Brothers in 1935.

And after a successful collaboration on a Broadway play with his brother, Philip soon joined him.

It wasn't until 1942 that the twins were assigned to write their career-defining film, Casablanca.

For roughly $400,000 in today's money, the screen rights for a stage play originally titled Everybody Comes to Ricks were bought.

A Moroccan city occupied by the French who were under Nazi rule in 1941.

Rick, the owner of the cafe, greets Czechoslovak resistance leader Viktor Laszlo and discovers that his wife, Ilsa Lund, is the same woman who left him without explanation in Paris, hours before Nazi troops stormed the city.

Rick must wrestle with his conscience.

Does he help Ilsa, the woman he loves, flee Morocco with her husband Viktor?

or give them up to German Major Strasser.

Jack Warner asked the Epsteins to adapt the initial play and Michael Curtiz to direct it.

Meanwhile, the producers secured Hollywood heartthrob Humphrey Bogart as Rick and Ingrid Bergman for Ilsa.

The cast was soon confirmed, but production was far from straightforward.

The Epsteins still had much of that old New York fighting spirit, a fact that made their relationship with their boss turbulent.

Casablanca was no exception to the rule.

After making a start on what would become one of the most famous screenplays of all time, Julius and Philip took a break.

They flew to Washington DC to work on something completely different, and in their absence, writers Casey Robinson and Howard Koch also contributed to the script.

As filming rapidly drew to a close, the twins have one more vital scene to write.

The ending.

The final act of Casablanca hinges on Ilse's moral conundrum.

Does she leave Victor to be with Rick, the man she still loves?