A couple of days back we discussed Orson Welles’ 1937 Broadway production of Julius Caesar. We had a couple of photos but there’s no film (like there is for the “Voodoo” Macbeth a year before).
However, there are a number of radio recordings Welles did of Caesar with his Mercury Radio Theatre.
Here’s a recording from March of 1938 (bare bones cut; 40:40).
Another from July of the same year (a more complete edit of the play, with narration; 1:29:43).
Here’s some rehearsal tape from September of the same year (with interesting introduction, tying in current world events to the play; 1:06:44).
And here’s a recording from the Ides of March 1944 (the Act Four quarrel scene between Brutus (Welles) and Cassius (Charles Laughton); 7:13).
All of the above are from the Internet Archive’s Orson Welles / Shakespeare Collection (archive.org).