Question: The American silent film The Unholy Three starring Mae Busch was filmed on what year?

Context articles: Mae Busch
Peacock Alley (1930 film)
Fazil (film)
The Unholy Three (1930 film)
Michael G. Ankerich
The Unholy Three (1925 film)
Love 'em and Weep
Married Flirts
The Triflers
Valencia (1926 film)

Mae Busch (18 June 1891 – 20 April 1946) was an Australian-born actress who worked in both silent and sound films in early Hollywood.
 In the latter part of her career, she appeared in many Laurel and Hardy comedies, where she frequently played Hardy's shrewish wife.
Peacock Alley is a 1930 American musical romantic drama film directed by Marcel de Sano, and starring Mae Murray and George Barraud.
 The film is a remake of the 1922 silent film of the same name in which Murray also stars.
 Aside from Murray being cast in the lead, the remake was largely different from the 1922 silent film.
 While Murray's character in the 1922 film was named Cleo, she was renamed Claire Tree in this film.
 George Barraud replaced Monte Blue as the male lead, who is now named Clayton Stoddard.
Fazil is a 1928 American silent drama film directed by Howard Hawks and written by Philip Klein and Seton I. Miller.
 The film stars Charles Farrell, Greta Nissen, John Boles, Mae Busch, Tyler Brooke and John T. Murray.
 The film was released on June 4, 1928, by Fox Film Corporation.
The Unholy Three is a 1930 American Pre-Code melodrama involving a crime spree, directed by Jack Conway and starring Lon Chaney.
 The film is a remake of the 1925 film of the same name, with both films based on the novel "The Unholy Three", by Clarence Aaron "Tod" Robbins.
Michael G. Ankerich is a biographer whose work focuses on American silent film and early twentieth century actors and actresses.
 Ankerich's interviews with the last remaining silent film stars were featured in "Broken Silence: Conversations With 23 Silent Film Stars" (1993) and "The Sound of Silence: Conversations with 16 Film and Stage Personalities Who Made the Transition from Silents to Talkies" (1998).
 His biography of silent film actress Mae Murray, "Mae Murray: The Girl with the Bee-Stung Lips," was named one of the top 10 must-read film books of 2012.
The Unholy Three is a 1925 American silent film involving a crime spree, directed by Tod Browning and starring Lon Chaney.
 The supporting cast features Mae Busch, Matt Moore, Victor McLaglen and Harry Earles.
Love 'em and Weep is a silent comedy short film starring Mae Busch, Stan Laurel and Oliver Hardy prior to their official billing as the duo Laurel and Hardy.
 The team appeared in a total of 107 films between 1921 and 1951.
Married Flirts was a 1924 American silent drama film starring Pauline Frederick, Mae Busch, and Conrad Nagel, directed by Robert Vignola.
 Julia Ivers wrote the screenplay based on a Louis Joseph Vance best seller, "Mrs. Paramor".
 The 'sophisticated' drama was considered quite daring at the time as the story centered on husbands being lured away from wives.
 The film is now considered a lost film.
The Triflers is a 1924 silent film society-drama directed by Louis Gasnier and starring Mae Busch.
 It was produced by B. P. Schulberg and distributed by Preferred Pictures and Al Lichtman.
Valencia, also known as The Love Song, is a 1926 American silent romance film directed by Dimitri Buchowetzki, who came over from Paramount to direct, and starring Mae Murray and featuring Boris Karloff in an uncredited role.
 Rumors of a surviving print persist.
 The film was a box office hit and the title song, "Valencia", was the top song in the U.S. for the year.