The original title of this film was "The River is Blue" and the director was to be Lewis Milestone. Kurt Weill even wrote music for the project that was never used (lyrics by Ann Ronell). The title was changed to "The Rising Tide" and "Castles in Spain," then finally to "Blockade." The topic of the Spanish Civil War was politically sensitive and there is some hint that the upheavals of the original project were due to the political content of the film.
Producer Walter Wanger was not deterred by pre-release threats of problems and boycotts from pro-fascist foreign governments. He responded, "Not only do we meekly take intimidation from abroad, but we jump obediently when almost anybody in this country says, 'Frog!' It's ridiculous, and I, for one, don't intend to continue. I'm going to release this Spanish picture as is, and if it's banned in Europe, I'll have to take my loss."
Disclaimer on film and connected paper - Note: Care has been taken to prevent any costume of the production from being accurately that of either side in the Spanish civil war. The story does not attempt to favor any cause in the present conflict,
This was one of two dozen Walter Wanger/Harry Sherman/Cinema Guild films originally released by United Artists, re-released theatrically in 1948 by Masterpiece Productions, and ultimately sold by them for USA television syndication in 1950. It was first telecast in Albuquerque Tuesday 25 April 1950 on KOB (Channel 4), in Phoenix Wednesday 10 May 1950 on KPHO (Channel 5), in Detroit Sunday 21 May 1950 on WXYZ (Channel 7), in Philadelphia Sunday 11 June 1950 on WFIL (Channel 6), in Cincinnati Saturday 17 June 1950 on WKRC (Channel 11), in New York City Saturday 1 July 1950 on WCBS (Channel 2), in Los Angeles Sunday 30 July 1950 on KTLA (Channel 5), in Chicago Sunday 6 August 1950 on WENR (Channel 7), in Cleveland Sunday 19 November 1950 on WXEL (Channel 9), in Boston Sunday 31 December 1950 on WNAC (Channel 7), and in San Francisco Saturday 27 January 1951 on KGO (Channel 7).
Final film of Dolores Duran,