declassified archives military archives

Non-written sources in military archives


The Committee of Military Archives thanks Kathleen Van Acker, our Secretary General, for her great commitment and active participation to this blog


The traditional idea we have of archives are piles and piles of old paper, boxes stacked in long racks. Archives, in the public opinion are text-based.

However this idea has changed, the mantra “no documents no history” is surpassed. Within the archival terminology the term “document” has evolved too, following the different evolutions in types of information flow.

In the 19th century, Jules Milechet: the famous historian and curator of “les Archives Nationales” in France, already stated that documents are only one sort of source among other sources.

We also see this evolution in the archival definition:
information or data stored on a medium and used as an extension of human memory or to support accountability. We don’t speak about “a document” any longer, but we use the word “a medium”. This medium can have different formats, in general we speak of:

  • written
  • visual
  • oral
  • 3 dimensional

To illustrate these different mediums we will show some of the different sources kept by the section Classified Archives (Belgian Ministry of Defence) and explain their importance in historical research.

Written sources

We are all familiar with the “traditional” archives, i.e. the written documents.

In the section Classified Archives the written archives are the biggest part of our collection. We have the military archives since the mobilisation in Belgium in 1939, so it is logical most of them are still written. Some examples are field journals, official documents, listings of prisoners, etc….

Royal decree concerning the Belgian Sûreté militaire, established 1st April 1915

Visual sources

Next to the written sources we have the visual sources. We are all familiar with photos and the sentence “a photo says more than a thousand words”. Next to written documents we have a lot of photos in our archives. We have the official documents, an example are the Personalkarte WWII, where you will find a photo of the prisoner with his personal data. For researchers in family history it is always an emotional moment to see their grandfather, great-grandfather as a prisoner.

Personalkarte (WWII)

Gail OKAWA did a study on Japanese prisoners during WWII describing her feelings when she came across a photo of her grandfather: “the first time I came across his mug shot in the INS file was especially chilling for me as I imagined his humiliation
(Gesa E. KIRCH and Liz ROHAN, Beyond the Archives, Research as a Lived process, 2008)

History becomes very real in this case.
We have more examples like this, next to the listings of prisoners of the STALAF and OFLAG prisoners camps, we have a collection of photos from those camps, mostly found in personal archives. They give an unique view of the life in those camps

Stalag baracks (WWII)
Stalag: prisoners cooking their meal (WWII)

Another example is the diary we found in the archives of the Tandel sisters.
The Tandel sisters were volunteers in the resistance during WWI and WWII. Two unmarried sisters, Laure and Louise, joined the Red Cross at the outbreak of WWI. Very soon they joined the resistance. When they got arrested by the Germans, Laure was sent to the Siegburg prison where she stayed 6 months. She wrote in her diary, wrote poetry, and made drawings. After her release she and her sister joined “La Dame Blanche” a resistance group in Belgium. During WWII Laure and Louise joined the resistance group “Clarence”. Two remarkable ladies, who left us a great amount of information about women in the intelligence world.

Drawing by Laure Tandel of her cell in the Siegburg prison (WWI)
Drawing by Laure Tandel of her cell in the Siegburg prison (WWII)

Oral sources

We don’t have a lot of oral sources in our archives, as said above, we mainly keep the more “traditional” archives. But we do have a piece of archive which is quite interesting: a tape of a encoded message from the GRU to a Belgian officer who was recruited as a spy.

During the Cold War, Colonel BINET was recruited by the GRU. During a meeting with one of his contacts in Vienna, he was spotted by the CIA who contacted the Belgian military intelligence service. After a surveillance operation, BINET was arrested.

The methods used by BINET and the GRU are very well documented by the records we received, but also by the objects we have. Not only are they an example of an oral source, but also of the three dimensional sources

Three-dimensional sources

In the BINET archives we have a lot of objects used by Colonel BINET and the GRU.

We are not exaggerating when we say they could be used in a James Bond film.
BINET used the obligatory briefcase with a secret compartiment to take classified documents home. They used hidden slips of paper with codes, secret ink etc… All of these object were transferred to the archives and give an unique view of the espionage methods used during the 80’s.

Binet’s suitcase with secret compartiment
Binet’s pen with hidden code
Binet’s wallets with codes written in invisible ink


In my experience as an archivist I can say that the written sources, certainly in the past, mostly give information about the political affairs and administration. They didn’t give a lot of information about people who didn’t held positions of power.

Luckily the scope of history has widened, and we find that information in the other sources, which I illustrated in my examples above.

I can state that the quote “no documents, no history” is not correct. I would like to believe that nowadays we can say “no trace, no history”. The written sources are still very important history, but they aren’t the only one. Archival sources can take all forms.

declassified archives military archives Military archives legislation

Declassification procedures in different countries: food for thought


The Committee of Military Archives thanks Kathleen Van Acker, our Secretary General, for her great commitment and active participation to this blog


One of the most discussed topics during our annual conferences is dealing with classified archives. Military archivists deal with these kind of archives on a daily base; we all have similar but also different legislations and directives. So we decided to give an overview of what we found online and what we learned during our discussions.

This summary doesn’t pretend to be complete, on the contrary, like mentioned above, it was mostly an online search and we had to deal with language barriers. It is an invitation for colleagues and researchers to add their information about declassifying procedures, the changes in legislation, etc… So please go ahead and comment in the comments section and send an e-mail to We will adapt this list on a regular base.






  • The Army History Directorate:
    • in 2020 all classified documents of the Directorate’s archive issued by Army institutions until 1955 were declassified
    • access to the more recent ones and those not issued by the Army still remain restricted








  • Thirty year rule”: all governmental records are released after 30 year (now 20 year)
  • Exemptions: Intelligence services have a “blanket approval” given by the Lord Chancellor to keep their records as long as they are classified, in order to protect national security.
  • More information: 


  • Declassification after 25 years after creation of the document.
  • Exemptions:
    • reveal the identity of a confidential human source, a human intelligence source, a relationship with an intelligence or security service of a foreign government or international organization, or a non-human intelligence source; or impair the effectiveness of an intelligence method currently in use, available for use, or under development;
    • 25X2 – reveal information that would assist in the development, production, or use of weapons 25X1 of mass destruction;
    • 25X3 – reveal information that would impair U.S. cryptologic systems or activities;
    • 25X4 – reveal information that would impair the application of state-of-the-art technology within a US weapon system;
    • 25X5 – reveal formally named or numbered U.S. military war plans that remain in effect, or reveal operational or tactical elements of prior plans that are contained in such active plans;
    • 25X6 – reveal information including foreign government information, that would cause serious harm to relations between the U.S. and a foreign government, or to ongoing diplomatic activities of the U.S;
    • 25X7 – reveal information that would impair the current ability of U.S. government officials to protect the President, Vice President, and other protectees for whom protection services, in the interest of national security, are authorized;
    • 25X8 – reveal information that would seriously impair current national security emergency preparedness plans or reveal current vulnerabilities of systems, installations, or infrastructures relating to the national security;
    • 25X9 – violate a statute, treaty, or international agreement that does not permit the automatic or unilateral declassification of information at 25 years.
  • More information:

ICMH Congress military archives

Declassification and GDPR in military archives

By Kathleen Van Acker, Archivist with the section Classified Archives (Belgian Ministry of Defense).

The Committee of Military Archives thanks Kathleen Van Acker, our Secretary General, for her committment and her participation to this blog after she presented “new privacy rules and declassificationin Belgium during the 2021 CAM meeting

A topic that is always present during CAM meetings is the classification and declassification of military archives. This year we once more discussed this topic, exchanging views and practices.

It was also part of my presentation. However classified information and declassification is only one problem archivists have to deal with. In my opinion privacy can be a much more difficult topic when dealing with information in military files. Both topics were discussed in my briefing where I presented the section Classified Archives (Belgian Ministry of Defense) and our regulations and methods for dealing with classified information and personal data.

An example of a declassified document in the section Classified Archives

Classified information and classified archives.

Military archives contain classified information, this is a reality military archivist have to work with.

They have to walk the thin line between providing information to researchers and be careful not to break the rules on classification or give information which may endanger national security or individuals.

Does this mean that classified archives are by no means accessible to researchers? No, after all the purpose of classification is to protect information, and not to keep information away from the public. 

With the passage of time classified information can become less sensitive, and may be declassified and made public.

In Belgian law only the person who classified the document can declassify the document or give his/her permission to declassify (art.5 de la Loi relative à la classification et aux habilitations de sécurité, 11 décembre 1998) Which means that a lot of requests are send to ask for declassification. This procedure is used in “ad hoc” demands: A researchers asks for information, the archivists scan the files and if they find a classified document they evaluate whether the information is still sensible. If not, they send a request to the person, organisation (or his successor) with a demand to declassify. When they get the official permission, the documents and/or file is also officially declassified and open to the public.

A second method is used for larger archives. It treats complete archive funds that are being declassified and transferred to the War Heritage Museum or the National Archives as a whole. The most recent example is the archive fund of World War I which was declassified and transferred to the War Heritage Museum. This procedure takes a lot of time. First a detailed inventory is made of the archives, including remarks about potential sensible documents. The inventory is examined by the Commission of Archives, which gives its permission to declassify, followed by an official declassification note from the Minister of Defense.

The presentation held by Kathleen Van Acker during the Congress in Athens on 29 August 2021

Personal data protection.

Archivists are used to dealing with personal data protection, but for the last couple of years the protection  of those data has been under steady attention and as a result of that the protection measures have become more and more extensive. 

Since 25 May 2018 we have the GDPR or General Data Protection Regulation in the EU, a binding legislative act which must be applied across the Union. The key principle of the GDPR is data minimisation. To use the terminology in the GDPR: “Personal data should be collected and processed only if it is really necessary to do so (…) only as long as it is necessary in order to achieve the purpose for which the personal data was collected” (art.5).

Luckily the GDPR left some room for exemptions, one of them is “archiving purposes in the public interest”, or archives would no longer contain any personal data in the future.
EU lawmakers acknowledged that archives are important and even necessary to enforce fundamental and democratic rights an stated that “personal data may be stored for longer periods insofar as the personal data will be processed solely for archiving purposes in the public interest, scientific or historical research purposes”(art.5).

This definition can be confusing to people not dealing with this kind of information, but they can trust archives services: they will not disclose their personal data incorrectly, because:

  • Archivists only select those documents for permanent preservation that are necessary for historical research or to enforce human rights;
  • Storing personal data is not the same as giving access: the closure period can vary in different countries. 

Important for historical research is that the GDPR protects personal data of living persons, not the personal data of deceased persons. It seems simple, but how can archivists know that the person is deceased? They can assume that persons born more than hundred years ago are no longer alive. In cases where the 100-years mark isn’t reached, archivists can ask for a prove of decease (eg. an obituary). 

The poster related to the exposition “History of the Belgian Military Intelligence and Security Service”.

It is clear that in case of a declassification request and handling personal data, archivists will have to make case-by-case assessments. Much to the frustrations of researchers sometimes, these procedures take time and a lot of careful consideration, but I learned that informing the researchers about this way of working and the tight legislation we have to deal with, makes them understand the delays or the refusal to access in the worst case. 

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