Question: Long John Silver was quartermaster under what 18th-century fictional captain?

Context paragraphs:
Long John Silver: Long John Silver is a cunning and opportunistic pirate who was quartermaster under the notorious Captain Flint.  Long John Silver had a pet parrot called Captain Flint, often seen sitting on his shoulder where she would nibble on seeds.  Silver claims to have served in the Royal Navy and lost his leg under "the immortal Hawke".  "His left leg was cut off close by the hip, and under the left shoulder, he carried a crutch, which he managed with wonderful dexterity, hopping about upon it like a bird.  He was very tall and strong, with a face as big as a ham—plain and pale, but intelligent and smiling."  ("Treasure Island" (1883) by Robert Louis Stevenson page 82).  He claims to have been the only man whom Flint ever feared.  Like many of Stevenson's characters, there is more than a modicum of duality in the character; ostensibly Silver is a hardworking and likeable seaman, and it is only as the plot unfolds that his villainous nature is gradually revealed.  His relationship with Jim Hawkins, the novel's protagonist and narrator, is interesting, as he serves as a mentor and eventually father-figure to Jim, creating much shock and emotion when it is discovered that he is in charge of the mutiny, and especially when Jim must confront and fight him later on.  Although willing to change sides at any time to further his own interests, Silver has compensating virtues: he is wise enough to pay attention to money management, in contrast to the spendthrift ways of most of the pirates, and is physically courageous despite his disability; for instance, when Flint's cache is found to be empty, he coolly stands his ground against five grown men despite having only Jim, a boy in his teens, to back him.

Captain Flint: Captain J. Flint is a fictional 18th-century pirate captain who features in a number of novels, television series, and films.  The original character was created by the Scottish writer Robert Louis Stevenson (1850-1894).  Flint first appears in the classic adventure yarn "Treasure Island", which was first serialised in a children's magazine in 1881, and later published as a novel in 1883.

John Silver (pigeon): John Silver was a war pigeon active with the United States Army in World War I.  He served with distinction during World War I.  He was knocked out of the air twice by cannon flak, but he got back up both times and completed his mission.  He lost an eye and a leg, so he was given an eye patch and a wooden leg, hence the name "Long John Silver".  He is also wearing the medal he was awarded. .  s of 2010 the animal is on display at the National Museum of the United States Air Force.

Long John Silver (film): Long John Silver, also known as Long John Silver's Return to Treasure Island, is a 1954 American-Australian Adventure film about the eponymous pirate from "Treasure Island", starring Robert Newton as Silver and Rod Taylor as Israel Hands.

Looking at Long John: Looking at Long John is an album by Long John Baldry released in 1966.  In 1995, "Long John's Blues" / "Looking at Long John" was released on CD.  It has since been re-released and remastered on "Looking at Long John: The UA Years".  The orchestral arrangements were by Bob Leaper.

Kit Taylor: Kit Taylor (born 1942) is an Australian actor, the son of Grant Taylor.  He made his acting debut as Jim Hawkins in the film "Long John Silver" (1954) and the associated TV series "The Adventures of Long John Silver".  He went on to have an acting career as an adult.

Pirates in popular culture: In English-speaking popular culture, the modern pirate stereotype owes its attributes mostly to the imagined tradition of the 18th century Caribbean pirate sailing off the Spanish Main and to such celebrated 20th century depictions as Captain Hook and his crew in the theatrical and film versions of "Peter Pan", Robert Newton's portrayal of Long John Silver in the 1950 film of "Treasure Island", and various adaptations of the Eastern pirate, "Sinbad the Sailor".  In these and countless other books, movies, and legends, pirates are portrayed as "swashbucklers" and "plunderers."  They are shown on ships, often wearing eyepatches or peg legs, having a parrot perched on their shoulder, and saying phrases like "Arr, matey" and "Avast, me hearty."  Pirates have retained their image through pirate-themed tourist attractions, traditional film and toy portrayals of pirates, and the continued performance and reading of books and plays featuring pirates.

Long John (bull): Long John #58x (2010 – February 21, 2017) was the Professional Bull Riders (PBR) World Champion Bull in 2015.  He tied for the title in 2016 with two other bulls (Bruiser and Pearl Harbor), but the tiebreaker went to his brother, Sweet Pro's Bruiser.  In 2015, he was the Professional Rodeo Cowboys Association (PRCA) Reserve Champion Bull, coming in second to Kish's #849 Crystal Deal.  In 2016, "Time Magazine" selected Long John for its 100 Most Influential Animals of 2016, for which he came in at 50th place.  Long John became both a fan favorite and a bull rider favorite by the end of his career.  The PBR CEO, Sean Gleason, said, shortly after his death: "Long John was a phenomenal athlete with the heart of a champion."

Long John Silver's: Long John Silver's LLC is an American fast-food restaurant chain that specializes in seafood.  The brand's name is derived from the novel "Treasure Island" by Robert Louis Stevenson, in which the pirate "Long John" Silver is one of the main characters.  Formerly a division of Yum!  Brands, Inc., the company was divested to a group of franchisees in September 2011.

The Adventures of Long John Silver: The Adventures of Long John Silver is a TV series about the Long John Silver character from "Treasure Island".  It was made in 1954 in colour in Australia for the American and British markets before the development of Australian television.

Supporting paragraphs: Long John Silver Captain Flint
Answer: Captain J. Flint