A series of unfortunate events

I have approached today’s blog post rather nervously because it’s by way of an experiment. In writing it, I have set myself a difficult task and only you can tell me how far I have succeeded.

Wallpaper with a context. This design for wallpaper (catalogue reference BT 42/14/144) is part of a volume of registered design samples (BT 42/14), which in turn is part of a record series (BT 42). This series is part of the records of the Board of Trade and related bodies (department code BT).

Wallpaper with a context. This design for wallpaper (catalogue reference BT 42/14/144) is part of a volume of registered design samples (BT 42/14), which in turn is part of a record series (BT 42). This series is part of the records of the Board of Trade and related bodies (department code BT).

My aim is to explain the concept of a ‘series’ of archival records in a way that is clear and useful, without either oversimplifying it or becoming too complicated and technical. 1 This is something that I have tried to do before, both as part of pre-prepared talks and ‘on the fly’ when answering questions in our reading rooms. Some of my attempts have been more successful than others and I think it’s time to seek some feedback on how I could improve my explanations. Constructive criticism is welcome! 2

Before I started writing, I looked at what some ‘classic’ authors, 3 a couple of 21st-century textbooks, 4 and some archive-related blogs 5 had to say about the subject, but these really only scratch the surface of what has been written before. 6

I have written this post as a set of Frequently Asked Questions, with my personal take on what the answers should (or could) be. Most of these are genuine questions that I have been asked at an enquiry desk in our reading rooms at least once.

What is a ‘series’?

A series means a set of records of the same type and the same origin. 7 Slightly more formally, it means a sequence of records with a relationship resulting from a shared history of creation, storage or use. 8 Typically, historical records in the same series either document the same activities or functions, or were created as part of the same filing system or process (or both of those things).

Are records in the same series always pretty uniform?

Not always. Some series consist of records that are all very similar to one another. Others are more miscellaneous in format or content. Some are entirely ‘natural’ – made up of records that have always been kept as a set or sequence – and others have been arranged (or reconstructed) by archivists. 9

Some series contain thousands of records and others only a few. Some contain records created over centuries and others cover a much shorter time period.

Why do archivists bother organising records into series?

It’s in the nature of archives that they normally come as sets of related records, not isolated single items. The value of records as historical or legal evidence very often comes from their collective nature and from their context – what we know about how and why they were originally created and used – as well as their content.

When organising records, archivists try to follow the ‘principle of provenance’, meaning that we group them together according to where they came from.

Particularly in the case of records originally made by larger organisations – such as the UK government bodies whose records we hold at The National Archives, or some businesses – this tends to involve multiple layers of sub-groupings. All records created by the same organisation are grouped together, and divided into progressively smaller units. 10 As far as possible, these layers, generally called ‘levels’, reflect either the administrative structure or the functions of the organisation. 11

This simplified diagram shows the place of the catalogue description for the design BT 42/14/144 in relation to other catalogue entries.

This simplified diagram shows the place of the catalogue description for the design BT 42/14/144 in relation to other catalogue entries.

Series are traditionally a mid-level layer. 12 Here at The National Archives, we normally distinguish at least three levels in our catalogue descriptions: department 13 (the records of a government body or a group of related bodies), series and piece 14 (the individual files, boxes, volumes, rolls, datasets, etc making up a series). Sometimes we include additional levels too.

Why are some series organised in date order, others in some sort of alphabetical order and others in random order?

One size doesn’t fit all. Many decades of collective experience have taught archivists that sorting everything into, say, date order for the sake of it isn’t a good idea.

Where possible, archivists follow the ‘principle of original order’, which means keeping the records within each series in the same sequence as they were maintained before they came to the archives. This is part of trying to preserve the context of the records.

Quite often archivists encounter records without any ‘original’ order. In these cases we have to devise a sequence that makes sense in terms of the content. The order of records within a series is never entirely random!

Wouldn’t it be easier just to group records together by subject? 15

Absolutely not. As well as having the disadvantage of destroying the context, this would be an unnecessary waste of time and effort. As many records reflect several different subjects, trying to organise records by subject would simply make a few topics easier to research and others a lot harder.

Archivists also try to be as unbiased as possible when arranging and describing records. 16 Organising records to reflect their origin and how the original creator kept them is the best way to allow them to speak for themselves.

It’s also worth remembering that records in the same series are very often about the same subjects as well. If a set of records had no subject matter in common, it’s unlikely that they would have been created or used together originally.

Does the system of catalogue references match how records are arranged into series?

Yes, our citable references at The National Archives follow the organisation of the records quite closely. Most other archives also use referencing systems that reflect how the records arranged, at least to some extent.

For records held at The National Archives, the letters in the catalogue reference signify the department and the first set of numbers normally indicate the series. Subsequent sets of numbers (separated by forward slashes) refer to pieces, and sometimes even to items within those pieces (such as specific letters within a bundle of correspondence).

For example, in the reference WO 78/406/3, the department is WO (for War Office), the series is WO 78, the piece is WO 78/406 and the item is WO 78/406/3. 17

Do I really need to know about series to do research using archives?

A qualified yes. It’s not necessary to understand what a series is to do some straightforward kinds of research, such as finding a person in a census returnby searching online. For anyone studying more complicated or open-ended topics, though, an awareness of the fact that records come in series is absolutely essential.

Using Discovery’s advanced search screen to restrict a search to catalogue descriptions of series.

Using Discovery’s advanced search screen to restrict a search to catalogue descriptions of series.

My experience is that researchers usually find the process of using archives easier and more effective if they have at least a basic understanding of a few technical terms (like series) and the principles behind how they work. 18

Can I use your catalogue to search just for series that I might like to investigate in more detail?

Yes. The advanced search screen of Discovery, our catalogue, includes an option for doing just that. Scroll down to the heading ‘Catalogue levels’ and click on ‘Show options’.

The catalogues of other archives often allow you to do this too, although the mechanics of doing it may be quite different.

Another way to identify series of records at The National Archives that may be relevant to your areas of interest is to use our online research guides.

Can I also use your catalogue to search just for records within a particular series?

Using the advanced search screen to search for records within series MAF 32.

Using the advanced search screen to search for records within series MAF 32.

Yes. You can use the advanced search screen to do this too. Scroll down to ‘Search within’.

You can also include series references in a basic search (for example, Kew AND “MAF 32”). This is often quicker but less precise.

Again, the catalogues of many other archives will allow you to do something similar.

One last question: are series always about unfortunate events?

No, of course not. I thought that the allusion was worth making, though, and not just because so many records relate to unpleasant things, such as the ever-present death and taxes, 19 in some way.

When I borrowed my title from a popular sequence of books, I did so for a reason. Records that are arranged by provenance form a kind of story: the histories of how they were created and of the people or organisations that made them. As I mentioned earlier, the principles of arrangement adopted by archivists are those that best allow the records to speak for themselves.

Records also contain other stories: the interconnected histories of people, places, events and ideas. When people use archives for research, they typically look at several (or many) different records. It is organising records to reflect the context of their origin that best allows researchers to understand them, to assess their relevance, and to or uncover the stories of the past.


  1. 1. Many present and past ideas about archives and how they should be managed are neither simple nor straightforward. Terminology can be confusing or even frustratingly imprecise. For instance, the word ‘archive’ itself is open to multiple interpretations and misunderstandings. Some of my footnotes hint at points that are more complicated than I’ve been able to discuss in a single blog post.
  2. 2. I have not been very concise here, for one thing.
  3. 3. S Muller, J A Feith and R Fruin, Manual for the Arrangement and Description of Archives, reissue of the 1940 translation by Arthur H Leavitt (Chicago, 2003); Hilary Jenkinson, A Manual of Archive Administration, revised edition (London, 1937); T R Schellenberg, The Management of Archives (New York, 1965).
  4. 4. Caroline Williams, Managing Archives: Foundations, Principles and Practice (Oxford, 2006); Jackie Bettington et al (eds), Keeping Archives, 3rd edition (Canberra, 2008).
  5. 5. Including this post from the British Postal Museum and Archive and this post from Library and Archives Canada
  6. 6. It’s only fair to mention that academic writers who have thought deeply about the issues involved have often challenged some of the ideas and principles underlying traditional archival practice.
  7. 7. Traditionally, British archivists called series ‘classes’, but series has now become the internationally accepted term in English. I think that series is a more intuitive and appropriate term than class because it implies a sequence as well as a set.
  8. 8. For a fuller definition, see General International Standard Archive Description (ISAD(G)), 2nd edition, section 0.1.
  9. 9. Another reason why some series are rather different from others is that archivists have interpreted the concept in slightly different ways at different times, in different organisations and in different national traditions.
  10. 10. Alternatively, we could say that individual records are grouped together, and then progressively aggregated into larger units.
  11. 11. It isn’t always possible to reflect both. In fact, provenance is often less straightforward than a single, layered hierarchy can represent fully.
  12. 12. Some archivists, especially in Australia, have decided not to group records together into units larger than series.
  13. 13. In other archives, this may be called a ‘fonds’, ‘record group’ or ‘collection’.
  14. 14. In other archives, this is normally called a ‘file’.
  15. 15. Somebody asked this in a comment on one of my previous posts. It’s a fair (and important) question.
  16. 16. Like many aspects of archival work, this is easier said than done.
  17. 17. There are some exceptions. For instance, in the reference CP 25/2/5/25/30HENVIIIEASTER, the series number is CP 25/2, not CP 25.
  18. 18. Many people find our online guidance on understanding the archiveshelpful.
  19. 19. Or even death taxes.


  1. David Matthew says:

    I would suggest that ‘Series’ are part of an overall collection of records from a department that cover a specified part of that organisation, usually a division or unit. The series does not contain all of the records on a particular subject but that division/unit’s actions and views at the time and reflect the limits of the department’s filing systems and the limited and sometimes out of date descriptions. For example Treasury used to have four series (Finance, Establishments, Supply and General (a mixture of the other three stated areas) but from c1948 that was divided into Divisions which continues to this day. So what you will get is multiple files on the same subject across the department but also because each Division had input into a subject there may be similar files on the same subject. This is how they were created and an artificial arrangement which would not be historically true as they will have been taken out of context. Indeed when the Public Record Office (PRO) was created Black and his other officers at PRO arranged records by subject, but without any series numbers and it is unclear when such numbers came into existence, probably when the public were allowed to see them.

    Researchers should be aware that what they are looking for may be described differently (often the file cover description is what has been catalogued, so for example if you looking for the records about the Poll Tax during the Thatcher eras then they can be listed as ‘alternatives to the rating system’. Divisions/units can often change and there should be a link to where the continuous or previous records can be found.

    1. Andrew Janes says:

      Thank you, David. I like your point that records ‘reflect the limits of the department’s [or, more generally their creators’] filing systems’. I can see myself using that phrase in future.

      Received wisdom has is that an embryonic version of the current referencing system dates back to the late 1920s, although consistent expression is quite a bit more recent.

  2. Dave King says:

    I found the overall post to be particularly useful in the way that you have covered the whole subject in a clear & concise fashion.
    I’d like to comment on the “arrangement by subject” question, as I think this opens up a link to a discussion on ‘what will be increasingly possible’. I agree 100% with your answer (to paraphrase: one researcher’s ‘subject’ is another researcher’s ‘poison’), but also with why the originator felt his question was important.
    The key to this is the distinction between the arrangement & referencing of records and the means of access to those records.
    Originally, these concepts were pretty much the same.
    Increasingly, they are diverging with the development of electronic catalogues & other means of access, which mean that the resolution of the ‘one record, many subjects’ conundrum is resolvable, via such concepts as categories (eg in wikis), subjects (Discovery) and tags (also in Discovery). This leads to references becoming less of an access issue, and more of a convenient means of organising records, which is what they are best at.
    Of course every solution leads to the next problem – how to resource the application of subjects/categories to individual records, and there I think the only viable answer is via crowd sourcing, something which is getting off the ground, eg Your Archives (categories) and Discovery (tags), but has some way yet to go.

    1. Andrew Janes says:

      Thank you, Dave. I’m glad you found the post useful.

      My current feeling (it’s an evolving thing…) is that the provenance-based arrangement (as more-or-less reflected in the referencing system) is _an_ arrangement rather than _the_ arrangement.

      You make a very valid point about arrangement and referencing not necessarily matching. The fact that our Discovery catalogue has both ‘Browse by hierarchy’ (i.e. by arrangement) and ‘Browse by reference’ options is testament to the fact that the two don’t always correspond precisely. This reminds me that some archives (though not The National Archives) make a distinction between ‘reference numbers’ (which reflect a hierarchical structure closely) and ‘finding numbers’ (which often don’t).

  3. Barbara Schenck says:

    Andrew, thank you for this post which explains in clear English the way things are organized ‘by provenance,’ and yes, I would agree that it is ‘an’ arrangement, and not necessarily ‘the’ arrangement — or not always the most useful arrangement.

    For example, the organization of records involved in chancery cases seems, by provenance, to jerk them out of context and put them with a collection of unrelated items that do the same thing in different contexts. Having them thus organized rather defeats the goal of seeing the records in their proper context. It also makes things very difficult when trying to gather all the items that might have been created in the hearing of a single case.

    While it might have originally been convenient for the office keeping the records to file them this way, I can almost guarantee you that most researchers don’t study them according to the ‘type’ of record they are, but rather in the context of an individual case. This seems, to me at least, one instance where a different sort of organization — by case — would be more useful. And as the records were created within the context of that case, it could be argued that removing them from their original context has created an ‘artificial’ organization which does the records and the researchers a disservice.

    Is there perhaps a plan afoot to provide cross-referencing to the various items in such cases so that pulling together all the documents is a less onerous process?

    Thank you.

    1. Andrew Janes says:

      Thank you for your comment Barbara. Apologies for not replying straightaway. I’m away from the office at the moment.

      When I made my off-the-cuff comment about ‘an’, not ‘the’, arrangement, I was (deliberately) conflating two different things:

      1) There isn’t always a single, clearly ‘correct’ provenance-based arrangement of – or ‘original’ order to – the records.

      I need to temper this by saying that even if there isn’t one right answer, nonetheless there may be incorrect ones. A solution that involves ignoring or breaking up a filing system that worked for the original creators is pretty certain to be a wrong one – however odd the original recordkeeping system may seem to present-day researchers. Conversely, a solution that reflects how the records were filed before they came to the archives can never truly be said to ‘jerk them out of context’.

      2) The links that researchers identify between records are, in effect, alternative (and probably equally valid) ‘arrangements’ of the same information. These can, and should, coexist and overlap with the records’ own inherent arrangement, although we can’t expect the structure of the catalogue to reflect them.

      The format and structure of many records relating to legal cases actually makes it impossible to rearrange them physically into any kind of artificial case files, even if we wanted to. This is particularly true of the bound volumes of Chancery decree and order books.

      As you suggest, a much more sensible and practical approach has been to improve the online catalogue descriptions in a way that makes it quicker and easier to identify records relating to particular cases. Some colleagues of mine have actually been pursuing this approach for many Court of Chancery records (with help from volunteers and the Friends of The National Archives). The number of records involved is vast, though, so completing this programme will take several years.

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