When the writers began to outline the story, the main character was British. Later they decided to move away a little from the context of the English in 19th century Argentina; it occurred to them that the character could be Danish and started to think of Viggo Mortensen as a possible choice for the lead role. They continued rewriting the film with him in mind until Mortensen himself also began to get involved and to provide lots of ideas, thus leading to his casting.
The script for this movie was 20 pages long.
Viggo Mortensen's involvement surpassed not only the producer capacity, but he also helped with the music, the poster and correcting the subtitles to Spanish, French and English.
Viggo Mortensen is fluent in Spanish. His character's stilted Spanish accent is a homage to his Danish father, who raised his family in Argentina and Venezuela.
Fabian Casas wrote a novelization of the film as he and Lisandro Alonso were writing the screenplay.