Here’s a viewers’ guide for the ages

845-866

“The Last Kingdom” (BBC America, Oct. 10): The Viking invasion again, this time set in 866 and told from the perspective of a nascent England of scattered kingdoms. Town and village names are shown in original Saxon, then translated into modern English.

“Vikings” (History, returns early 2016): When last we left Ragnar Lothbrook, he and his fellow Danes got their clocks cleaned while attempting to conquer Paris in 845.

1270s

“Marco Polo”(Netflix; second season in production): Handsome young man goes far and wide to discover naked Asian ladies. The Internet was made for his ilk.

14th century (c. 1315?)

“The Bastard Executioner” (FX, premiered Sept. 15): This bloody, bloody drama is set in Wales sometime after the reign of King Edward I. Cast members, even the pretty ones, were required to wear yellowed and browned teeth.

1500-1535

“Masterpiece: Wolf Hall” (PBS, aired in spring 2015): A delectably dour portrait of political scheming during the tumultuous reign of Henry VIII. Darkness. Viewers get a real feel for life by candlelight.

1693

“Salem” (WGN America; returns in spring 2016): Witches terrorize panicked Puritans, only this time the witches are real.

1715

“Black Sails” (Starz, returns in 2016): Tales of the Caribbean pirate menace, set just before the events of “Treasure Island.”

1745

“Outlander” (Starz, returns in 2016): A British woman on vacation in Scotland in 1945 touches an ancient standing stone that transports her back to 1743. Season 2 picks up in France during the Jacobite risings. kilts and more kilts.

1777-1781

“Turn: Washington’s Spies” (AMC, returns in 2016): Colonial rebels from Long Island devise new ways to warn Gen. George Washington about the British army’s next move. invisible ink and other primitive encryption techniques.

“Masterpiece: Poldark” (PBS, aired in summer): In 1781, a gallant and handsome redcoat officer returns from the American war to run a copper mine and winds up marrying his kitchen maid.

1860s

“Mercy Street” (PBS, premieres Jan. 17, 2016): Filmed in Virginia, PBS’ first domestically produced drama in ages is about an Alexandria hospital at the outset of the Civil War.

“Hell on Wheels” (AMC, final episodes will air in 2016): Post-Civil War corruption/revenge drama set against the fast-and-furious completion of a transcontinental railroad in the Midwest. Story last left off in 1867.

Late Victorians

“Penny Dreadful” (Showtime, returns in 2016): Florid monster mash set in London in 1891 features Victor Frankenstein, Dorian Gray, werewolves, vampires, demons. And “Ripper Street” (BBC America, also returns in 2016): is a crime procedural set in London that started in the year 1889 and is now in 1894. Meanwhile, on another plane entirely, “Another Period” (Comedy Central, recently renewed for Season 2): is a send-up of crunchy-gravel dramas, set in tony Rhode Island in 1902.

1925

“Downton Abbey” (PBS, final season begins Jan. 3, 2016): What’s this show? Never heard of it. Next.

1932

“Masterpiece: Indian Summers” (PBS, premiered Sept. 27): Languid, steamy drama about mostly-white-people problems during the British Raj. flop sweat.

World War II

“Masterpiece: Home Fires” (PBS, premieres Oct. 4): Charming drama about rural British women gearing up in 1938 to do their part in the looming war. Keep Calm and Wear a Snood.

“Manhattan” (WGN America, returns Oct. 13): Drama set in Los Alamos, N.M., as American scientists and engineers secretly build and test the atomic bomb. Season 2 picks up on July 16, 1945 — three weeks before the United States drops a nuke on Hiroshima.

Early 1960s

“The Man in the High Castle” (Amazon, premieres Nov. 20): Set in 1962, this alternate-reality drama shows life in a former United States that fell to Germany and Japan in World War II. These ‘60s don’t look like much fun. For starters: no rock ‘n’ roll.

“Call the Midwife” (returns in 2016): On a more cheerful note, they’re still birthin’ babies in London’s East End, with increasing hints of modernization. Season 5 will pick up in 1961.

1966

“Masters of Sex” (Showtime, Sundays at 10): Season 3 moved forward a few years into the sexual revolution, as Virginia Johnson and Bill Masters released their first book, “Human Sexual Response.” (Frankly, it was more fun when the show was set in the prude ‘50s.)

1967

“Public Morals” (TNT, Tuesdays at 10): Drama stars Edward Burns as an Irish-American cop in the NYPD’s vice unit.

“Aquarius” (NBC, renewed for Season 2): David Duchovny plays an L.A. police detective who tangles with the Manson family. Left off in January 1968 — 18 months before the Tate-LaBianca murders.

1972

“Vinyl” (HBO, premieres in early 2016): Martin Scorsese and Terence Winter (with help from Mick Jagger): are behind this drama about a New York-based record label desperate to find bigger acts. Stars Bobby Cannavale and lots of sideburns, shag carpeting and tube tops.

1979

“Fargo” (FX, returns Oct. 12): Noah Hawley takes Season 2 of the Minnesota murder epic back to 1979 and the pre-Reagan malaise. Jesse Plemons (“Friday Night Lights,” “Breaking Bad”): with feathered hair.

1982

“Wicked City” (ABC, premieres Oct. 27): L.A. noir on the Sunset Strip in the early-MTV, Rodney-on-the-ROQ days. the birth of RATT.

1983

“The Americans” (FX, returns in early 2016): Season 4 creeps closer to glasnost — can Philip and Elizabeth keep daughter Paige quiet about their spying? Paige is in her room wearing out her LP of Yaz’s synth/new-wave classic “Upstairs at Eric’s.”

1985

“Red Oaks” (Amazon, premieres Oct. 9): This coming-of-age story at a New Jersey country club is kind of a “Flamingo Kid” set in the John Hughes era. Crimped hair.

“Halt and Catch Fire”(AMC, Season 2 concluded in August; renewal status unknown.): An improved second season flash-forwarded from ‘83 to ‘85, focusing on the race to build an online gaming network.

1980-something

“The Goldbergs” (ABC, returned Sept. 23): This loud-family comedy was originally set in 1985 but isn’t a stickler for chronological accuracy. How else to explain the re-enactment of John Cusack’s boombox moment from 1989’s “Say Anything …”?

1995

“Fresh Off the Boat” (ABC, returned Sept. 22): Chinese immigrants move to Florida and open a restaurant. Li’l Eddie Huang is wild for mid-’90s hip-hop.

2002

“Better Call Saul” (AMC, returns in early 2016): A prequel to “Breaking Bad,” which took place in the late ‘00s.

2065

“Minority Report” (Fox, premiered Sept. 21): Steven Spielberg consulted a team of futurists for the movie version; the TV show (set 10 years after the movie): takes all of its visual cues from there, including the ubiquity of personalized advertising. mega-skyscrapers in Silver Spring, Maryland.

2090-ish?

“Westworld” (HBO, premieres in 2016): Complete overhaul of the 1973 sci-fi film about a Wild West frontier that’s actually an amusement park populated by synthetic androids. Set in “the near future.”

2400-ish?

“Into the Badlands” (AMC, premieres Nov. 15): This martial-arts sci-fi series starring Daniel Wu is set “several centuries in the future” in the American Midwest.