Martin Padway is struck by lightning in 1938 and finds himself in sixth-century Rome, on the verge of its ruin at Justinian's hands and the onset of the Dark Ages. He may be able to save civilization, if he can only get the ruling Goths to grasp the ''value'' of his innovations...

Written by Creator/LSpragueDeCamp.
!! Tropes in ''Lest Darkness Fall'':

* AlternateHistory
* CatchPhrase: Thomasus the Syrian banker reacts to statements he considers outrageous by saying, "Did you hear that, God?"
* ChangedMyJumper - Martin's wearing a light wool suit, necktie, modern shoes and hat when he arrives. No one seems to particularly notice. He switches to local clothing not long after, but insisting on having his tunics modified to include pockets.
* TheExile: Belisarius. After he is captured during the first Byzantine invasion of Italy, he [[HonorBeforeReason refuses to accept parole]]. When Justinian is informed of this, he sends an angry reply dismissing the general and telling him to join the enemy (just as Padway expected from his knowledge of the emperor's jealousy and suspicion).
* FeelingOppressedByTheirExistence
-->"You don't like the Goths?"\\
"No! Not with the persecution we have to put up with!"\\
"Religious persecution. We won't stand for it forever."\\
"I thought the Goths let everybody worship as they pleased."\\
"That's just it! We Orthodox are forced to stand around and watch Arians and Monophysites and Nestorians and Jews going about their business unmolested, as if they owned the country. If that isn't persecution, I'd like to know what is!"
* GivingRadioToTheRomans - Notable in that one of the first and most important inventions he introduces is brandy. In itself, useless. For making money and building a place in society, invaluable.
** Padway tried to introduce quite a few innovations, with varying degrees of success. Arabic numerals and double-entry bookkeeping are readily adopted; on the other hand, as of the end of the novel he still hasn't managed to produce gunpowder weapons or a working mechanical clock.
* TheGoodChancellor: After navigating himself and the kingdom through political turmoil and war, Padway eventually settles down into the role of King Urias' quaestor.
* LongGame: Some of Padway's ideas are designed to [[SocietyMarchesOn nudge the culture]] in more enlightened directions as well as to serve the needs of the moment. For instance, he convices the king of the Goths to emancipate serfs in order to recruit them for defense against the Byzantine invaders (and undercut the institution of serfdom). Toward the end of the novel, he convinces the king to raise needed revenue with a new tax on slaves (with the intent of increasing the tax until slavery dies out).
* NonAnswer: Whenever someone asks his religious affiliation, Padway says that he's a "Congregationalist", which he describes as the closest thing his home country has to the questioner's religion. This keeps him out of trouble.
* OneManIndustrialRevolution - Distilleries, the telegraph, the printing press, the telescope...
* RescueRomance: After Padway rescues Mathaswentha from a [[AndNowYouMustMarryMe forced marriage]], the two are attracted to each other until he realizes just how [[ValuesDissonance ruthless she is by his standards]]. He manages to extricate himself without [[WomanScorned incurring her wrath]] by setting her up with Urias instead.
* {{Sequel}}
** S. M. Stirling wrote one called "The Apotheosis of Martin Padway," where time travelers go back to 585 AD -- about half a century after the events of the novel -- to see the Great Man who restored the Western Roman Empire.
** B. Munro [[ wrote a scenario]] describing the four hundred years after Padway's arrival.
* TrappedInThePast
* WhatYearIsThis - Martin tries to ask people the date in his shaky Latin, and at first gets the year in the old Roman calendar, then has to ask how many years since Christ was born to get the proper year (which turns out to be 533 AD).

!! Tropes in "The Apotheosis of Martin Padway"
* GodGuise: When time travelers (from the tenth century AD in the timeline created by Padway's actions) rescue him from a hostile mob, his ascension in a beam of light is taken as proof that he was a saint. [[StableTimeLoop Which is what their history recorded.]]
* HappilyEverAfter: Padway learns that the outcome of his half-century of work is an ultra-advanced civilization arising in the tenth century AD (the lowest depths of DarkAgeEurope in his original timeline). Better still, he is free of the aches and pains of old age -- his rescuers have [[WeWillHavePerfectHealthInTheFuture a cure for that]], and the story ends with Padway joyfully anticipating a new life of studying and discussing the new timeline's history.
* LaserGuidedKarma: Martin Padway's, "Fifty years of politics and administration and warfare and engineering... None of them his chosen profession, just the things he had to do to survive and keep the darkness from falling..." ultimately result in him being canonized as a saint of science and tolerance, which accelerates the timeline's development to the point where it could send time travelers after him.
* PowderKegCrowd: The events of the story are driven by an outbreak of rioting -- an economic recession has put the populace on edge, a football defeat provided the spark, and Justinian's agents are taking advantage of the opportunity to cause trouble.
* StableTimeLoop: Not from Martin's home time period, but the new timeline records that "Martinus of Padua" did not die, but "[[GodGuise ascended to heaven in a beam of light]]"... because time travelers rescue him from a screaming mob with a glowing antigravity beam.
* UngratefulBastard: Thanks to Padway's medical innovations, Justinian is still alive half a century after the events of the novel[[note]]In real-world history, he died in 565 AD, twenty years before the time of the story[[/note]]. So is his grudge and determination to settle the score.