Henry Fonda had just turned 31 when filming started. Annabella is supposed to be playing a character of around 20/21, who claims to be 23, but was in fact approaching 30, only one year younger than Fonda.
The first three-strip Technicolor movie shot in Europe; completed in 1936, and bearing a 1936 (MCMXXXVI) copyright statement on the title card, but not released until 1937.
Wings of the Morning is a quotation from Psalm 139, verse 9: "If I take the wings of the morning, and dwell in the uttermost parts of the sea..."
Europe finally had the Technicolor cameras but not yet any laboratory where the rushes could be processed to look at. As a result, causing some delay, the filmed footage was flown to Hollywood for lab work and then flown back to England, a cumbersome process.
Annabella plays a Spanish Gypsy in this film. The actress herself was French; the script tells us she is 23 years old; in real life, she had been in films for ten years, and was approaching thirty.