Gli uomini non guardano il cielo (1952) (eng. The Secret Conclave)
Unfortunately only in Italian.
"The film traces the Pope's early life as a village priest, then follows him directly to the Vatican. The Papal installation, seldom seen before on film, is recreated on location at the Sistine Chapel, with several genuine cardinals in attendance. Dramatic conflict occurs when the Pope-to-be nearly refuses the honor, feeling himself unworthy. Also adding bite to the proceedings are the WW I scenes, detailing Pius X's efforts to put an end to the carnage. Secret Conclave ends with Pius X's death during Mass, a scene handled as tastefully as the rest of the film. "
Traditional Latin Mass filmed on Easter Sunday in 1941 at Our Lady of Sorrows church in Chicago. The film presents the ceremonies of the Missa Solemnis or Solemn High Mass in full detail with narration by then Mgr. Fulton J. Sheen.