Kurt Johnstad has signed on to draft the Dan Lin-produced The Lost Legion at Warner Bros. Deadline reports that the 300 screenwriter will tackle the ancient history epic.

The film, set in 53 BC, tells the true story of a Roman legion defeated in battle in the Middle East and sold into slavery in the land that would become Mongolia. The soldiers were then rescued by Chinese warriors from the Han Dynasty.

Johnstad's credits also include the recent Act of Valor and the upcoming 300: Rise of an Empire, which hits theaters on August 2.

Chris Darling, Susan Feiles and Jon Silk will serve as executive producers.