Here is a collection of observations I've made about page history oddities. I find out if there are page histories to merge by checking deleted contributions of early editors, and checking articles on place name lists like List of urban areas by population or national place name lists. I also use the lists at WikiProject History Merge to find pages to history merge. Sometimes, I can use old copies of Wikipedia to restore the missing history or find pages with lost edits (see my further notes on this and the "Resolved" section. If you find any other page history oddities, feel free to let me know.
Page history started to be reliably kept and dated after the conversion to Phase II software in January 2002 (see Wikipedia:Usemod article histories for caveats). Therefore, all history from that time onwards should theoretically be accessible. However, some page history has disappeared entirely due to moves and deletions.
The following situation is typical:
Page A is moved to Page B by cut and paste, either before the page move function became available to non-sysops, after which it was used more often and it was more reliable, or by a user who was not aware of or could not use the page move function.
Page B is moved back to page A with the move function, thus deleting page A's old history.
The deleted revisions are cleared from the database, meaning that the deleted history of page A is gone permanently. The deleted revisions were last cleared on 8 June 2004 in a database crash, and were previously cleared on 3 December 2003, when the Wikipedia database was transferred to a new server. (the mechanism for storing deleted revisions was established on 10 August 2002.)
Any page history deleted before 8 June 2004 is no longer in the current Wikipedia database. Some very early revisions appear in Nostalgia Wikipedia, a copy of the Wikipedia database from 20 December 2001, and some old database dumps are available, which can be used to find and restore missing edits; for more information about how I copy those edits to the current Wikipedia database, see User:Graham87/Import. The following articles have missing history which seemingly cannot be restored by sysops:
Fukui Prefecture – the page history may have been lost due to the same bug that affected the other two entries; most significantly, this page move occurred between the time of the first and second surviving edits in the page's history.
Ali – The title of the page containing its old history, "Ali Ben Abu Talib", was deleted in March 2004 because it was an "empty redir", probably meaning that it was orphaned.
Massachusetts – The text of many of its early edits is missing due to a database glitch, as described at T147146.
Darfur – legitimate but short article at this title deleted in September 2003 because it was written by an editor at the IP address 165.228.132.11, which had started vandalising Wikipedia nearly a year after creating the article.
Benedict Arnold – old history deleted in December 2003, because the page had very little content at the time; it may have been vandalised.
Edward VIII abdication crisis – the title with the first edits, "Abdication crisis", was deleted in January 2003 because the text had been moved by cut and paste to the article's new title, "Abdication crisis of 1936" (per the January 2003 database dump).
İzmir, Domo (NHK), and IMI Desert Eagle – in all three of these cases, a copyvio was introduced, the whole article was deleted, then the pre-copyvio text was replaced without the page history. In the case of "İzmir", this occurred in April 2004; in the other two cases, this occurred in May 2004. Selective undeletion was introduced in December 2004).
Orgy – This page was moved from the title "Orgy (sex)" to "Orgy" in August 2003; however, the title "Orgy (sex)" was deleted in February 2004 as an orphaned redirect. The page history of "Talk:Orgy (sex)" has survived, and I have history merged it with Talk:Orgy. See my edit to the talk page.
John Pell – deleted in June 2003 because it only contained the text "I love GG~". However, there is a perfectly adequate article from Rouse History of Mathematics in the May 2003 database dump, so perhaps the page was vandalised.
Santalum – an article about this subject was deleted in March 2004 because it contained nonsense; however, there is a reasonable article at this title in the May 2003 database dump.
Posthuman – an article formerly at this title was deleted in September 2003 as "graffiti"; the latest version in the May 2003 database dump was very short.
Jeff Chandler – a page at this title was deleted in February 2004 because it was not in English; however there is a reasonable article containing information on both the actor and the boxer with this name in the May 2003 database dump.
Vile and Ve – the history of text that was merged into the pages now at "Vili" and Vé was deleted in March 2004 per a deletion discussion. I have imported the only available edits from the May 2003 Wikipedia database dump, but they may or may not be enough.
Fifth Estate – the history of a disambiguation page at this title was deleted in April 2004 to make way for a page move.
The Pas – the original history was at the title "A page that will never be written unless some jerk writes it", which was used as an example red-link title. In this case the history was deleted in October 2002.
Replicant – the history of text that was merged from the title "Replicant (Blade Runner)" was deleted in February 2004 because the page was an orphaned redirect.
Bookmarklet – the old history at the title "bookmarklets" was deleted in September 2002; the reason given in the deletion log is "new page created in error: deleted by request of Milly".
Carloman of Bavaria – the title containing its earliest history, "Carloman, king of Bavaria", was deleted in August 2002; the deletion reason was: "because I created it and spelled it wrong".
Talk:Postmodern philosophy – the old title, "Postmodern philosophy/Postmodern philosophy talk", was permanently deleted because it is in the Deletion log/28 February – 19 July 2002. Even after importing the relevant history from the Nostalgia Wikipedia and the March 2002 database dump, there still appear to be missing edits.
Talk:Time travel – the old title, "Talk:Time Travel", was deleted in August 2002 because it was a broken redirect. I imported the surviving edits from the Nostalgia Wikipedia, but there are still gaps in the history.
Talk:Perth – early history at the title "Talk:Perth WA" was deleted in December 2002 as a "strange holdover with no discussion not copied to another article"
Talk:Serial polygamy – the talk page history was deleted in January 2004 after a page move (see this edit). I have imported two edits from the May 2003 database dump, but at least one edit is missing per the above link.
Talk:Luigi Dallapiccola – the history of early edits to this talk page at the title "Talk:Luigi Dallapiccola&actionedit" was deleted in December 2002.
Wikipedia:Wikipedia Day and Wikipedia:Magnus Manske Day (with their respective talk pages) – when they were moved from the main namespace to the Wikipedia namespace (except for the Magnus Manske Day talk page which was simply deleted), Magnus Manske, the subject of the latter page, permanently deleted the resulting redirects with all the old vhistory; see the Deletion log/28 February – 19 July 2002. An interesting result of these actions is that the Wikipedia Day page gives a creation date of 15 January 2002], but there is no way to verify this date. Revisions after December 2001 survived the conversion from UseModWiki to MediaWiki reasonably well, so there should have been *some* evidence of the pages from January 2002. However, one edit survived from Magnus Manske Day, and I have now history merged it to Wikipedia:Magnus Manske Day. I also imported the only surviving edits from the March 2002 database to the "Wikipedia Day" page and its talk page.
Wikipedia:Who, Why? – the very first edits were at at least one of the titles "Wikipiedia (Who, Why)" or "Wikipiedia: (Who, Why)". Both of these pages were deleted in May 2003.
These cases have been either mostly or entirely fixed using old copies of the Wikipedia database. Unless otherwise specified, they have been completely resolved.
Aberdeen – The early history at the title "AberdeenScotland" was deleted in November 2003 because it was a CamelCase page.
Rochester, New York – the first edit was at a title with unusual spacing, "Rochester ,New York", which was deleted in December 2002 as a "Misspelled page".
History of the United States – The old title of this page, "History of United States", was deleted in August 2002 after it was moved to its current title using the page move function. Due to this deletion, the history of that page from the UseModWiki era was not imported in September 2002. I have imported the surviving history from the Nostalgia Wikipedia, but there is clearly a gap in the history.
Geography of the United States – The old title was deleted in August 2002. The given reason was "old style subpage, no history (already redirect in February), no links"; the history had just not yet been imported from the UseModWiki database.
Inuit languages and Talk:Inuit languages – the titles containing the earliest edits to these pages, Inuktitut and Talk:Inuktitut, were deleted in August 2003 to make way for a page move.
Some old subpages – During the UseModWiki era of Wikipedia, subpages were used extensively. The part of the subpage's title after the "/" usually began with an upper-case letter, like "Subpage/Test". However, if it began with a lower-case letter, like "Subpage/test, its UseModWiki edits were not imported during the mass-import of these old edits in September 2002. I've imported some of these missing edits from the Nostalgia Wikipedia, but there are still pages with lost edits, such as at User:Arcade~enwiki (formerly at the title "Wikipedians/arcade"), User:Ddroar/articles, User:Gareth Owen/inprogress, Religious affiliations of Presidents of the United States (formerly at the title "President of the United States of America/religious affiliations"),User:Taw/contributions, and Wikipedia:Find or fix a stub, formerly at the title "Wikipedia utilities/find or fix a stub".
Some old talk pages – Before namespaces were introduced to Wikipedia during the conversion to the Phase II software in late January 2002, talk pages were at the title "Pagename/Talk". However some talk pages were mistakenly placed at the title "Pagename/talk"; these pages were swallowed up during the conversion from UseModWiki in January 2002. I have imported all the relevant content and edits to these lost talk pages from the Nostalgia Wikipedia, but it only goes up to 20 December 2001. Therefore talk pages with the suffix "/talk" created between 20 December 2001 and 25 January 2002 are permanently lost. An example of such a page that may have contained significant discussion is "MMORG/talk", per this edit; see this move log about the title of the talk page.
Scooby-Doo – its old title, "Scooby Doo, Where Are You?" was permanently deleted according to the Deletion log/28 February – 19 July 2002. I imported a missing edit from the March 2002 database dump, but had to estimate its timestamp, because it was listed as 15:51, 25 February 2002 (UTC) due to a database glitch (see below).
West Indies – I'm not entirely sure why this edit was lost; it may have been something to do with the previous edit being a blank edit recorded as being by Unknown, but none of the other similar edits have this problem.
Alcalá de Henares – early edits to this article were at the title "Alcalá de Henares", which was deleted in April 2004 as a "[r]edirect page with broken HTML entity in the title"
Ottawa (disambiguation) – the history of the first attempt to create this disambiguation page at the title "Ottawa" was deleted in July 2003 to make way for a page move.
Luís Figo – the title that contained the first two edits to this page, "Luis Figo, a very disloyal player", was deleted in February 2003 because the page name was opinionated ("POV") and the article was empty.
Simple API for XML – its original title, Simple API for XML, was deleted, but it's not in the deletion log; it must have happened some time between 22 January and 17 May 2003 (UTC).
Lothlórien – some old history at the title "Lothlorien" was deleted. It's not in the deletion logs, but it probably has something to do with this page move.
Talk:Florence – the first edits to this talk page were deleted in April 2003 to allow the talk page's title to match that of the main page.
Talk:Frankfurt – the early talk page, which was at the title "Talk:Frankfurt am Main", was deleted in February 2003 as an empty talk page, during the process of moving the article from "Frankfurt am Main" to "Frankfurt"; I have imported the relevant edits to Talk:Frankfurt. I have also restored some old history of an early disambiguation page that was at the title "Frankfurt" to Talk:Frankfurt/Old history.
Many old user and user talk pages – When Wikipedia used the UseModWiki software, there were no namespaces, so all the user pages were in what we now call the main namespace. Much user page history was lost because many user pages were moved by cut and paste from the main to the user namespaces, and the main namespace history was deleted before the most recent purge of deleted revisions. This phenomenon predominantly affects user pages of people whose usernames were at the start of the alphabet. Examples include AxelBoldt, Ed Poor, and Eloquence. I have restored all user page history deleted in April and May 2004 that had not already been imported from the Nostalgia Wikipedia ; most of the user pages deleted at that time began with the letters A to E. Most of the unrecoverable user page history is listed at Wikipedia:Usemod article histories. Notable examples are User:Bryan Derksen, User:LC~enwiki, User:Lee Daniel Crocker, User:Magnus Manske, and User:Rmhermen. An interesting example of user page history that was deleted through an unusual method is User:Jason Richey, which was deleted in May 2004 after this discussion.. Another example is User:Invictus~enwiki (then at "User:Invictus), which was deleted in October 2003, also after a discussion. Yet another example is User:RoseParks/sandbox which used to be at the title "R P Sandbox" and was deleted also in October 2003 after this discussion. One more example can now be found at User:Jmccann~enwiki/old; it was deleted after this discussion because it had been blanked. A fifth example involves User talk:Scott (usurped)~enwiki and is discussed in the March 2002 database dump section.
Wikipedia:Arguments – An essay that was featured on the "Annoying users" page from December 2002 (when it was written) until May 2003, it was deleted as a "rant" in February 2004, but I have imported its edits from the May 2003 database dump (both the January and May 2003 database dumps contained the same edits). I've moved the page to User:Ed Poor/Arguments.
Kenya – The old history was deleted in February 2004 to make way for a page move. I have restored the history from before the temp page was created – see this edit. There may have been significant edits afterwards, but there are none in the May 2003 database dump.
James VI and I – The old history at "James I of England" was deleted in July 2003 to make way for a page move. I have restored most of it from the May 2003 database dump; the only gaps involve a few minor edits.
List of governors of Halland County – relevant edits at the title "County Administrative Board of Halland", which were later moved to "Halland County Administrative Board", were deleted in March 2004 by the author of the original page.
Funabashi, Chiba and its talk page – was moved by the author from "Funabashi" to "FUnaba" and then "Funaba" (see a discussion about the title, starting with the text "Taku, are you up for a WikiProject called Japanese prefectures"). The mistitled pages were deleted in February 2004 because they had been tagged with a speedy deletion template.
Former Qin – in December 2003, the title "Former Qin Empire" was moved to "Fomer Qin"; shortly afterwards, that title was deleted as a typo. I've restored the relevant history from the May 2003 database dump, but there may be missing intervening edits.
Canada goose – history at "Canada Goose" deleted in May 2003 to make way for a redirect; there are small gaps in the surviving page history.
Polygonal number – this page was originally created at the title "Jacquerie27", the username of its author, probably by mistake. That page was deleted in January 2004 as a "test blanked by author".
Talk:Vittorio Emanuele, Prince of Naples – the history of a talk page message at the title "Talk:VIctor Emmanuel of Savoy" (which was later blanked by its author) was deleted in February 2004; the given deletion reason was: "no content, no history".
When the Pawn... – the initial version of this article, which was moved by cut and paste to "When the Pawn Hits the Conflicts", was made at a truncated version of the full album title to fit in MediaWiki's 255-character limit: "When the Pawn Hits the Conflicts He Thinks Like a King; What He Knows Throws the Blows When He Goes to the Fight, and He'll Win the Whole Thing 'Fore He Enters the Ring - There's No Body To Batter When the Mind Is Your Might, So You Go Solo, You Hold Your". This title was deleted in September 2003.
British Guiana 1c magenta – the history was probably lost due to this page move. Considering the gap in available edits, the difference between the last imported edit and the earliest edit from 2004 is remarkably small.
I have restored some page history that was deleted due to page moves. Most of these operations were trivial, like this one at Accra. However, the following are interesting cases and show the problems with cut and paste moves. See my logs dealing with:
In another science fiction franchise, the Palpatine article also had missing edits. Its history was moved to "Palpatine, Dantius", a name for the character cpoined by SuperShadow, who ran a Star Wars website, and then the page was moved by cut-and-paste back to Palpatine. The "Palpatine, Dantius" page was redirected to the SuperShadow article then moved to Dantius Palpatine; the redirect was deleted after a deletion discussion for the SuperShadow article, taking all the early history of the Palpatine page with it.
If the deleted revisions had been cleared out or there was a bad database crash, the page histories mentioned above may have become permanently inaccessible.
When a revision is added to the database, it is assigned an ID number, which is one more than that of the previous revision. Thus, in general, a low revision ID number will indicate an early edit while a higher revision number will indicate a more recent edit. Revision ID numbers can be a reasonable way to estimate the date of a revision, with some caveats.
Edits made when Wikipedia used UseModWiki were imported to the current Wikipedia database on 20 September 2002; therefore they have revision ID's over 200,000. The edit with a revision ID of 1 is not Wikipedia's earliest edit, but it is the first edit to be added using the Phase II software.
Page transfers via Special:Import or manually on the server also result in "out-of-order" revision IDs. Revision IDs do not increase monotonically with time, and you should never rely on this. --brion (talk) 16:42, 20 October 2008 (UTC)[1]
Another situation in which there can be incorrect timestamps is a result of early versions of MediaWiki. When pages were moved over redirects, the edit history of the newly created redirect would show the date and time when the overwritten redirect was created. There are more details in the section of the page move guidance about moving over a redirect, along with an example at Talk:PETA.
Incorrect timestamps can also affect the reported creation times of accounts at places like the list of all users, because this information wasn't oficially recorded in the database until the introduction of the user creation loginSeptember 2005.
Sometimes, the first visible edit to a talk page can have an earlier timestamp than that of the corresponding article. This can happen for several reasons, including copyright violations (where early article history is deleted) and unusual page moves. With my encouragement, my friend Codeofdusk wrote an extended essay about this topic, which can be found at User:Codeofdusk/ee.
^Out-of-order revision IDs are associated with some historical bugs. Until May 2017, the inconsistent ID numbers could cause problems when checking diffs, as diff navigation was based on the revision ID of edits rather than their timestamps (see T4930). Before the MediaWiki 1.18 update, the software also calculated the number of intermediate revisions between diffs by using revision ID's rather than timestamps; that result was incorrect when the order of the revision ID's did not correspond to the dates of the edits. An example of this phenomenon was at this edittoTalk:Netherlands, which now displays correctly as of the MediaWiki 1.18 update.
