How did the transition from Fox to Universal come about?
Basil Rathbone and Nigel Bruce starred in two Sherlock Holmes films for Fox which were set in the 1890s. Then they made twelve more for Universal, only those were set in contemporary times.
How did the transition come about? Did Universal purchase the rights from Fox or was Sherlock Holmes in the public domain by this point and Fox was unable to stop Universal from casting the same principle actors in the lead?