Original sentence: In 2006, Hutton Gibson reversed his position on the Siri Thesis, asserting that this theory was based on a mistranslation of an article written on October 27, 1958 by Silvio Negro for the evening edition of the Milan, Italy-based Corriere della Sera..   A similar event also happened in 1939; in that case a confusing mixture of white and black smoke emanated from the Sistine Chapel chimney
Edited sentence: A similar event also happened in 1939; in that case a confusing mixture of white and black smoke emanated from the Sistine Chapel chimney.In 2006, Hutton Gibson reversed his position on the Siri Thesis, asserting that this theory was based on a mistranslation of an article written on October 27, 1958 by Silvio Negro for the evening edition of the Milan, Italy-based Corriere della Sera