History Main / YearZero

* J.R.R. Tolkien's timeline in both ''Literature/TheHobbit'' and ''TheLordOfTheRings'' was meticulously kept. Frequent dates were given on the in-universe calendar (in the case of The Lord of the Rings both in Shire Reckoning and the larger calendar of Middle-earth). Additionally, each culture kept time based on their own internal reckoning, with years based on significant events: The Hobbits followed Shire Reckoning, with Year Zero on the founding of the Shire, while Gondor and Rohan had their own calendars as well. Middle-earth on the whole broke timekeeping down into different Ages whose first year was decided by specific events. Tolkien paid so much attention to his calendar system that he even rewrote the ''entire chapter'' of Faramir and Frodo overlooking the waterfall at Henneth Annûn because he realized that the phases of the moon he used didn't match his previously established timeline!

** A literal example of this trope comes from Cambodia, where the Khmer Rouge regime under Pol Pot declared 1975, the year that that Khmer Rouge insurgents were able to seize control of the Cambodian state, to be Year Zero of a new calendar.

** A more subtle example would be in the New Fishman saga. [[spoiler: The oldest of the Fishman princes desires to return it all to 'zero.' This refers to wanting to undo and do away with the bigotry the fishman/merfolk have with humans and vice versa. It's achieved when Luffy stops Hody, saves the island and is given blood by Jimbe, symbolic as it was forbidden to give humans blood due to a past event involving Fisher Tiger. The prince notes to his deceased mother that they achieved, expressing the desire for a better future for the races,]]

[[folder: Comic Books]]

[[folder: Live Action TV]]

[[folder: Real Life]]

* ''ComicBook/FantasticFour'' is the starting point of Marvel's sliding timescale, which roughly work like this; the time in Marvel is always "now", and everything in continuity is supposed to have happened within around a 10 to 14-year timespan. It is called a sliding timescale because the fact that the end point is always the present drags older stories forward in time; this can pose problems for heroes with ties to a specific era. Sometimes details can change: Iron Man originally had his original story in the Vietnam War though this has now been changed to the Middle East (at least in his films), but characters tied to a specific era can be harmed. While they just need to lengthen the amount of time Captain America (a WW2 veteran) spends frozen, Magneto (a Holocaust survivor) is forced to be older and older.

* This was averted by the Gregorian dating system used throughout the world. There is no year zero, and it is one of the calendar's base assumptions. Things that happened before the birth of Christ (the starting point of the calendar) are calculated in negative years Before Christ, counting down not to Year Zero, but Anno Domani 1: that is, there is a direct skip from 1 BC straight to AD 1! (Due to errors in calculations, the actual birth of Christ may lie anywhere from 6 BC to AD 6.)[[note]]The calendar's creator was limited by the fact that his society's mathematicians had no concept of zero yet.[[/note]] The lack of a year zero on the Gregorian dating system has led to practically everyone placing the start and end points of each century wrong in the generations after its introduction. For instance, when supercentarian Emma Martina Luigia Morano died in 2017, it was common to hear sources misreport her as having been the final living person born in the 19th century, when in reality, she was just the last person born in the 1800's. The ''actual'' last living child of the 19th century was Nabi Tajima, born in August of 1900. One notable gag on ''Series/{{Seinfeld}}'' makes light of this common mix-up, in which Newman accidentally books his New Year's Eve party a year later than intended thanks to him asking to reserve it for the New Millennium.

* This was averted by the Anno Domini dating system used throughout the world. There is no year zero, and it is one of the calendar's base assumptions. Things that happened before the birth of Christ (the starting point of the calendar) are calculated in negative years Before Christ, counting down not to Year Zero, but AD 1: that is, there is a direct skip from 1 BC straight to AD 1! (Due to errors in calculations, the actual birth of Christ may lie anywhere from 6 BC to AD 6.)[[note]]The calendar's creator was limited by the fact that his society's mathematicians had no concept of zero yet.[[/note]]

* ''ComicBook/FantasticFour'' is the starting point of Marvel's sliding timescale, which roughly work like this; the time in Marvel is always "now", and everything in continuity is supposed to have happened within around a 10-year timespan. It is called a sliding timescale because the fact that the end point is always the present drags older stories forward in time; this can pose problems for heroes with ties to a specific era. Sometimes details can change: Iron Man originally had his original story in the Vietnam War though this has now been changed to the Middle East (at least in his films), but characters tied to a specific era can be harmed. While they just need to lengthen the amount of time Captain America (a WW2 veteran) spends frozen, Magneto (a Holocaust survivor) is forced to be older and older.

* ''Franchise/TheElderScrolls'' universe has several Year Zeros, at the beginning of every new 'era'. It's common practice to put the era before the year when announcing a date, for example "Third Era, Year 433". The first four games take place in the 5th century of the third era (roughly - ''[[VideoGame/TheElderScrollsArena Arena]]'' covers the last year of the 4th century), and ''[[VideoGame/TheElderScrollsVSkyrim Skyrim]]'' takes place in the third century of the fourth era.

* In ''Literature/TheLeftHandOfDarkness'', the Karhide calendar counts ''every'' year is Year One and other dates are counted forward or backward from it. Historical discussions usually refer to kings' regnal dates and other great events for consistency. An alternate calendar used by the YoMeshta religion date from their prophet's birth.

* ''LyricalNanoha'' measures time based on the new Mid-Childa calendar, which according to the Fate's AsYouKnow talk in episode 14 of ''Anime/MagicalGirlLyricalNanohaStrikers'', began during the period when physical-based weapons were banned and {{Magitek}} became the standard. This was the time when the TSAB had fully established themselves, building their main branch in Dimensional Space and their land-based HQ in Mid-Childa.

** Fans tend to attempt to create the regular version of this with at least the Universal Century timeline, since there are a handful of specific dates given that are tied to a day of the week. This can be used to narrow down 2047 as the earliest possible year for the switch to the new calendar (2045 is the last AD date mentioned in any official timelines, but based on [[Anime/MobileSuitGundam0080WarInThePocket January 14th 0080 falling on a Monday]] and [[Anime/MobileSuitZZGundam 0088 being a leap year]] the changeover couldn't have happened then, assuming they didn't skip any dates or change the way leap years are distributed when the calendar was overhauled. It's also worth noting that WordOfGod has since declared all the official timelines that mention the AD era non-canon).

** Fans tend to attempt to create the regular version of this with at least the Universal Century timeline, since there are a handful of specific dates given that are tied to a day of the week. This can be used to narrow down 2045 as the earliest possible year for the switch to the new calendar.

* In Frank Herbert's ''Franchise/{{Dune}}'', the imperial calender starts at the creation of the Spacing Guild, which holds a monopoly over interstellar transportation. It is never explained why this event was chosen as the reference over, say, the coronation of the first emperor or the discovery of the spice.

* The calendar in the Spanish webcomic ''Webcomic/CincoElementos'' is based on a date called "Day Zero", when there was an all-out war that made the whole country collapse (curiously referred to by no other name than the "Day Zero war"). However, no date has been given so far in the comic, we only know the base of the calendar. (In fact, the author played with this in a chapter, trying to get fans off track in the timeline before [[spoiler:revealing that Rubéola wasn't Matarratas's real sister, when Matarratas's father had been stated to be 3 in the Day Zero.]]) Current fan speculation has the first chapter at the year [[spoiler:32]].

* The time when Nazi Germany was defeated by the Allies and reconstruction efforts began was known as "Die Stunde Dull" or "Das Jahr Null" (Zero Hour / Year Zero) to German citizens. It combined a feeling of defeatism, utter shock, delusion, and hope for the future.

** The Star Wars BBY/ABY (Before/After Battle of Yavin) calendar differs from most real-life examples in that 1 BBY and 1 ABY are the same year. The transition between BBY and ABY happens at the exact moment that the Death Star was destroyed.

* The ''Franchise/AceAttorney'' series frequently uses months and days for dates. But it usually refers to years only by reference (two years after a case, 5 years earlier, etc). However, a year is given for one particular event: the DL-6 incident happened in 2001 (December 28, to be exact). From this one fixed point, we can deduce the exact date of pretty much every case and event in the entire franchise.

For obvious reasons, Year Zero is often invoked for authors who use [[ComicBookTime sliding timelines]]. For example, the formation of the Franchise/FantasticFour was occasionally used as the Year Zero of MarvelComics continuity, with 'present-day' stories occurring about 10 years after this. [[ContinuitySnarl This does not always work perfectly.]]

*** Two pieces of side-information do give a very good idea of when the AC timeline is, however: the logo for the circus where Trowa Barton hides out says "Since 1667", and the novelization of the TV series says that the circus is about to celebrate its 600th anniversary, putting AC 195 somewhere around 2267 -- which would place Year Zero in the neighborhood of 2075.

** The use of the Battle of Yavin as a starting point for a calendar makes more sense if you remember the OpeningCrawl for the first ''Film/StarWars'' film, which mentioned that just before the movie begins, the Rebels had won their first stand-up battle against the Empire. The scene where one Imperial officer is very nearly BoardToDeath for having a [[AssholeVictim disturbing lack of faith]] has the Imperial officers discussing what to do about this recent development. So the Battle of Yavin presumably works because it was A) close to the beginning of the Rebellion proper, and B) a much more significant victory than [[OvershadowedByAwesome whatever happened before the film started rolling.]]

* When Kagome travels to the past in ''Manga/InuYasha'', she plops down into Japan's UsefulNotes/SengokuJidai, a century of continuous civil war and bloodshed. Because no exact dates are mentioned it would be anyone's guess as to what year it is when she goes back in time. The main clue the fandom has used to try to put a date to the era comes from one of the very first episodes, where a young samurai mentions UsefulNotes/OdaNobunaga, but considers him to be unimportant and an idiot[[note]]Nobunaga eventually brutally conquered much of Japan and his successors finished the unification and established the government that ran the country for the next 250 years[[/note]]. Since there is a rather short window of time where Nobunaga was known, but ''not'' as a terrifying, ruthless, slaughter-happy BadAss, fandom uses this to get a rough idea of when the story is supposed to be taking place.

* This was averted by the Anno Domini dating system used throughout the world. There is no year zero, and it is one of the calendar's base assumptions. Things that happened before the birth of Christ (the starting point of the calendar) are calculated in negative years Before Christ, counting down not to Year Zero, but AD 1: that is, there is a direct skip from 1 BC straight to AD 1! (Due to errors in calculations, the actual birth of Christ may lie anywhere from 6 BC to AD 6.)

* The Year Zero event in ''OnePiece'' is generally portrayed as the founding of the World Government, which occurred approximately 800 years ago. This event is the foundation of the ''One Piece'' world as it is now and the end of the Blank Century, a period which has very few surviving historical records and is illegal to study.

[[folder:Webcomics]]
* The calendar in the Spanish webcomic ''[[CincoElementos 5 Elementos]]'' is based on a date called "Day Zero", when there was an all-out war that made the whole country collapse (curiously referred to by no other name than the "Day Zero war"). However, no date has been given so far in the comic, we only know the base of the calendar. (In fact, the author played with this in a chapter, trying to get fans off track in the timeline before [[spoiler:revealing that Rubéola wasn't Matarratas's real sister, when Matarratas's father had been stated to be 3 in the Day Zero.]]) Current fan speculation has the first chapter at the year [[spoiler:32]].