B-movie Mayhem...Masque of the Red Death, seventh in the Corman-Poe cycle

Synopsis from Wikipedia:
The Masque of the Red Death is a 1964 horror film directed by Roger Corman and starring Vincent Price.[2] The story follows a prince who terrorizes a plague-ridden peasantry while merrymaking in a lonely castle with his jaded courtiers.[2] The screenplay, written by Charles Beaumont and R. Wright Campbell, was based upon the 1842 short story of the same name by American author Edgar Allan Poe,[2] and incorporates a subplot based on another Poe tale, "Hop-Frog'". Another subplot is drawn from Torture by Hope by Auguste Villiers de l'Isle-Adam.

It is the seventh of a series of eight Corman film adaptations largely based on Poe's works made by American International Pictures.

Odds and ends about Masque of the Red Death from the interview with Roger Corman featured on the MGM Midnite Movies DVD double feature release (which also includes Premature Burial):

Corman feels Masque of the Red Death is one of the better of the Poe films, and indeed of all of his films. Fall of the House of Usher was his choice to go forward with first, but he originally wanted to Masque to be released second…but because he was worried about being accused of stealing stylistic choices from Ingmar Bergman (a big influence on Corman), he waited to produce and release Masque later and released The Pit and the Pendulum next instead.

AIP had doubled Corman’s budget from $100,000 to $200,000 for these new fan- dangled colour Poe pics!

The Hop-Frog short story (Edgar Allan Poe) was combined into the story of Masque of the Red Death in later drafts—the previous drafts came off a little thin, plot-wise.

Corman didn’t have to audition Vincent, of course, but cast the other roles in Masque, having them do some improvisation, too. Hop-Toad’s wife was cast as a child (with a woman's voice dubbed in).  

Masque had the highest production value of all the Poe films.  They also spent 4-5 weeks shooting rather than the usual 3, and shot in England (securing a tax credit), rather than in America, where early Poe films had been shot.

A Man for All Seasons set flats were used for Masque, and Corman's team built the rest of the set around that, giving the film a much “bigger” look.

The Kennedy assassination happened while they were shooting—a big shock for Vincent and Corman, especially. They had a moment of silence at the time of the JFK's funeral.

Corman met Paul McCartney through lead actor Jane (who was his friend…she was from Liverpool, too)—he stopped in for lunch with Jane and Corman on his way to his first major London concert with the Beatles!

CAST:

• Vincent Price as Prince Prospero
• Hazel Court as Juliana, his mistress
• Jane Asher as Francesca, a peasant girl
• David Weston as Gino, Francesca's lover
• Nigel Green as Ludovico, Francesca's father
• John Westbrook as The Red Death (uncredited)
• Patrick Magee as Alfredo
• Paul Whitsun-Jones as Scarlatti
• Robert Brown as Guard
• David Davies as Lead villager
• Sarah Brackett as Grandmother
• Skip Martin as Hop-Toad, a dwarf jester
• Verina Greenlaw as Esmeralda, Hop-Toad's dwarf lover
  

Some critical reaction from the Wikipedia page:
Eugene Archer of The New York Times wrote, "The film is vulgar, naive and highly amusing, and it is played with gusto by Mr. Price, Hazel Court and Jane Asher ... On its level, it is astonishingly good."[12] Variety declared, "Corman in his direction sets a pace calculated to divert the teenage taste particularly, and past experience with Poe makes him a worthy delineator of this master of the macabre. In Price is the perfect interpreter, too, of the Poe character, and he succeeds in creating an aura of terror."[13] The Monthly Film Bulletin wrote, "Unquestionably Roger Corman's best film to date, The Masque of the Red Death has passages of such real distinction that one wishes he could be persuaded to take himself more seriously ... Where most films of this nature tend simply to pile on the blood, here there is a genuine chill of intellectual evil, because Vincent Price, initiating horrible tortures with a characteristic air of sadistic glee, also conveys a genuine philosophical curiosity as to the unknown territories into which his quest for evil may lead him."[14]

The film was not as successful as other Poe pictures, which Sam Arkoff attributed to it being "too arty farty" and not scary enough. Corman later said, "I think that is a legitimate statement. The fault may have been mine. I was becoming more interested in the Poe films as expressions of the unconscious mind, rather than as pure horror films."[5] Nonetheless, Corman says the film is one of his favourites.[15] Andrew Johnston, writing in Time Out New York concluded: "Elaborate sets and costumes and Nicolas Roeg's lush technicolor photography make this as close as Corman ever came to real greatness."[16]