After emigrating to the United States from Hitler's Germany (with stopovers in various other countries in between, among them the USSR), Brecht translated and re-worked the first version of his play in collaboration with the actor Charles Laughton. The result of their efforts was the second 'American version' of the play, entitled simply Galileo, which to this day remains the most widely staged version in the English-speaking world. This version differed in tone from the original, as Brecht felt that the optimistic portrait of the scientific project present in the first version required revision in a post-Hiroshima world, where science's harmful potential had become more apparent. This second version formed the basis for Losey's 1975 film adaptation for American Film Theatre under the title Galileo with Topol in the title role.
In September 1947, Brecht was subpoenaed in the US by the House Un-American Activities Committee for alleged communist connections. He testified before HUAC on 30 October 1947, and flew to Europe on 31 October. He chose to return to East Germany and continued to work on the play, now once again in the German language. The final German version premiered at Cologne in April 1955.
Matej Danter offers a readily-accessible and detailed comparison of the early, the American, and the final German versions.
In 2013 the Royal Shakespeare Company performed a new version of the play based on a "pared down" translation by Mark Ravenhill; the Swan Theatre production received a favorable review from the veteran theater critic Michael Billington.