Maurice Costello
Costello was born in Pittsburgh, Pennsylvania to Irish immigrants Ellen (née Fitzgerald; born 1853) and Thomas Costello (born 1852). He made his film debut in 1908, but was long believed to have debuted in "Adventures of Sherlock Holmes; or, Held for Ransom" (1905), supposedly playing the lead in what is regarded as the first serious film to feature the character of Sherlock Holmes, since it was preceded only by the 30-second comedy film "Sherlock Holmes Baffled" (1900). However, Holmesian scholar Leslie S. Klinger has written that the identification of Costello in the role is flawed. Klinger states that the first identification of Costello with the role was in Michael Pointer's "Public Life of Sherlock Holmes" published in 1975 but Pointer later realized his error and wrote to Klinger stating
The Hound of the Baskervilles (1939 film)
"The Hound of the Baskervilles" marks the first of the fourteen "Sherlock Holmes" films starring Rathbone and Bruce as Holmes and Watson, respectively. It is also notable as the earliest known "Sherlock Holmes" film to be set in the Victorian period of the original stories; all known previous "Holmes" films, up to and including the 1930s British film series starring Arthur Wontner as Holmes, had been updated to a setting contemporaneous with the films' release. It is also the only film in the series to be a strict adaptation of its source material, while subsequent installments would feature original titles and incorporate various elements of different stories.