Between "The Devil and Kate" and "Martha" which has more acts?
Martha (opera) Martha, oder Der Markt zu Richmond ("Martha, or The Market at Richmond") is a "romantic comic" opera in four acts by Friedrich von Flotow set to a German libretto by Friedrich Wilhelm Riese and based on a story by Jules-Henri Vernoy de Saint-Georges.
Lady Macbeth of the Mtsensk District (opera) Lady Macbeth of the Mtsensk District (Russian: "Леди Макбет Мценского уезда" , or "Ledi Makbet Mtsenskogo uyezda") is an opera in four acts and nine scenes by Dmitri Shostakovich, his Opus 29. The libretto, jointly written by Alexander Preys and the composer, is based on the novel of the same name by Nikolai Leskov. (The opera is incorrectly named "Lady Macbeth of Mtsensk" on several commercial CD and DVD recordings.)