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Citadel of Lille, France
Proposal status: Approved (active)
Proposed by: 501ghost
Tagging: castle_type=citadel
Applies to: node Nodes, area Areas
Definition: The fortified centre of a city

Draft started: 2022-10-03
RFC start: 2022-10-03[1][2]
Vote start: 2022-10-18
Vote end: 2022-11-01


Schematic image of a fortress

Citadels are historic fortifications inside cities that served as defensive cores. They are often bastioned and may even feature defence in depth with ditches and glacis (see defensive_works=*).

Difference between citadels and fortresses

This question was asked on the tagging mailing list. Essentially, fortresses are the defensive walls and other structures that surround a city centre. Citadels are enclosed fortifications within or on the edge of protected city centres. Fortresses and citadels do not always coexist.

The schematic image here represents a fictional fortress, in which number 36 is the citadel.

Proposed changes

This proposes that the tag castle_type=citadel gets added to the list of tags on castle_type=*. If the proposal is approved, this tag will be given the status of "approved". The status of castle_type=* will remain unchanged, as this is outside the scope of this proposal.


Citadels are major landmarks in several cities, mainly but not exclusively in Europe. They used to serve important military functions, but nowadays most citadels are either repurposed for civilian use or are partially demolished.

Citadels are currently often tagged either as historic=fort or as historic=castle + castle_type=fortress, neither of which explain adequately what citadels are.

This tag is neither intended nor expected to break any statistical usage records as there are only so many citadels in the world, but it serves to capture the function of these fortifications in a way that is not yet covered by existing tagging schemes.

Why not propose historic=castle and castle_type=* before this?

This question was asked on the discussion page, but as explained there, historic=castle is already a widely accepted tag with "de facto" status which I won't bother proposing, and castle_type=* has some notable issues with current documented values that in my opinion should be resolved first before the key can be put forward in a proposal.

How to map

Citadels should be mapped just as any other historic=castle: as a node node at the centre or as an area area along the outlines.

Note that outworks are sometimes included in the outlines of citadels and other fortifications. There seems to be no consistency or documented guideline on whether they should be included or left out, and this is outside the scope of this proposal.


List of citadels on Wikipedia


Voting closed

Voting on this proposal has been closed.

It was approved with 10 votes for, 1 vote against and 1 abstention.

  • I approve this proposal I approve this proposal. --501ghost (talk) 10:00, 18 October 2022 (UTC)
  • I approve this proposal I approve this proposal. -- Something B (talk) 10:04, 18 October 2022 (UTC)
  • I approve this proposal I approve this proposal. -- Sdicke (talk) 10:12, 18 October 2022 (UTC)
  • I oppose this proposal I oppose this proposal.
(My apologies, for not having participate in this discussion - too many activities at the same time.)
My main problem is with the definition of terms. The Wikipedia Citadel page says "A citadel is the core fortified area of a town or city. It may be a castle, fortress, or fortified center".
This seems to be in contradiction with the definition used in this proposal: This proposal says "A citadel is type of castle", and the Wikipedia article states "A castle is a potential type of citadel".
In addition there are (rare ?) cases where the entire city is a citadel. See Palmanova.
And what about the many different undocumented de-facto tagging approaches that are mentioned on the talk page?
--voschix (talk) 14:27, 18 October 2022 (UTC)
Thank you for voicing these concerns. At the moment I think it makes sense to continue with this already present and relatively well-known tagging scheme so mappers can map citadels in a consistent way with a documented tag. I agree with what you say, but it is outside the scope of this proposal and should instead be included in a future rework of castle_type=*. When that time comes, I will be the first to accept that castle_type=citadel may then be deprecated. --501ghost (talk) 00:40, 19 October 2022 (UTC)
If you agree that the current proposal is unsuitable and already think about future deprecation of the tag you are about to introduce then my suggestion would be to redraw the current proposal and stop voting now.—-Dieterdreist (talk) 07:45, 19 October 2022 (UTC)
  • I abstain from voting but have comments I have comments but abstain from voting on this proposal. Similar to what voschix said, in Greece many ancient fortifications especially those built on hills, contain the cities aswell besides the core, and usually named acropolis, which in Greek translates the same as citadel, but in contradiction with the meaning you specify of just the defensive core.
    An example, in Argos, the castle on top is the acropolis which contained part of the ancient city and in the middle and highest point of the hill is the main fortress. That, in English, isn't referred as citadel, the whole of the castle is referred as citadel few times though.--Jimkats (talk) 14:42, 18 October 2022 (UTC)
  • I approve this proposal I approve this proposal. --Emilius123 (talk) 15:25, 18 October 2022 (UTC)
  • I approve this proposal I approve this proposal. --Jedrzej Pelka (talk) 17:37, 18 October 2022 (UTC)
  • I approve this proposal I approve this proposal. --Tjuro (talk) 07:36, 19 October 2022 (UTC)
  • I approve this proposal I approve this proposal. --Reino Baptista (talk) 18:27, 30 October 2022 (UTC)
  • I approve this proposal I approve this proposal. --Cyrille37 (talk) 21:57, 30 October 2022 (UTC)
  • I approve this proposal I approve this proposal. --OSMRogerWilco (talk) 11:08, 31 October 2022 (UTC)
  • I approve this proposal I approve this proposal. --EneaSuper (talk) 12:01, 31 October 2022 (UTC)

Post-vote comments

  • I oppose this proposal I oppose this proposal. I don’t believe citadels should be generally mapped as castles (while it would probably ok for some of them), and this should be made much more clear in the proposal (including tags for other cases that aren’t castles) if this is your intention. Otherwise we will end up with people creating castles for citadels where it isn’t appropriate (i.e. this would change the meaning of castle if approved). Castle:type is well introduced with values for defensive and generally values where citadel does overlap if applicable: , there is fortification_type=* which seems more suitable for the term citadel. —-Dieterdreist (talk) 13:43, 8 November 2022 (UTC)
You're late to the party; the voting period has already ended. That said, I agree with you that this tagging scheme is not ideal. To be honest, I decided to document this tag mainly so we would have any single documented tag for citadels, because there simply wasn't one before.
castle_type=* has several issues, and overhauling or replacing it would be a big undertaking. @Martianfreeloader: has also shown an interest in the topic and seems to share our concerns. If we keep an open mind, maybe the three of us can work something out that the community can also agree with. --501ghost (talk) 14:04, 8 November 2022 (UTC)