With correspSearch you can search through indexes of different letter
collections (digital or print) by sender, addressee, location written,
location sent, and date. To this purpose a website and a technical
interface are provided. The web service collects and evaluates
TEI-XML data in the ‘Correspondence Metadata Interchange’ format.
The web service correspSearch is operated and developed according to the
Reference System: The web service aims to help
users with their research by offering a central location to search for
letters, and by guiding them to the original publication.
Academic Data: The web service is based on the data
from letter-indexes of editions or repositories that are edited
according to academic criteria.
Conceptionaly Open: There is no focus on a
particular time period or place. This allows for new kinds of research
questions to be explored.
Open Access: Data is only collected that is under a
free license, and the data from the web service continues to be under a
free license and is thus available for further use.
Open Interfaces: correspSearch offers technical
interfaces that are open and well documented. Other projects can easily
query and use the data.
Open Standards: Data exchange and data processing
are based on open standard formats and technologies.
Letters are considered some of the most valuable sources for historical
research. Not only does their content cover a variety of different themes,
events, persons, etc., but letters also depict networks between people.
Yet due to editorial and practical reasons historical letters are generally
only partially edited—focusing often only on one person or on the
correspondence between two persons. In order to address questions on topics
like relationship networks, it is necessary to do elaborate research using
multiple editions of letters. This challenge has been long recognized in the
academic community. Wolfgang Bunzel visualizes a solution, focusing on
correspondence from the Romantic era:
“the creation of a decentralized, preferably open digital platform,
based [...] on HTML/XML and operating with minimal TEI standards,
which is extensible in different directions and allows for existing
web portals and websites to contribute at the lowest possible cost.
This doesn’t require some kind of super structure which covers the
entire amount of letters from the Romantic era (which could not be
estimated exactly, anyway) but rather an intelligent linking system,
which associates existing documents with one another. The creation
of such nexus will naturally lead to research possibilities from
searches for persons and places to specific keyword-based searches
Wolfgang Bunzel: Briefnetzwerke der Romantik. Theorie – Praxis –
Edition. In: Anne Bohnenkamp und Elke Richter (Hg.): Brief-Edition
im digitalen Zeitalter (=Beihefte zu editio Bd. 34) Berlin/Boston
2013. p. 109-131, here p. 117. (Own translation)
The web service ‘correspSearch’ takes a step in this direction, collecting
the letter metadata from separate editions and repositories and making the
data available through open interfaces, based on the foundations of TEI-XML
and under a free license. Through this service the indexes of different
digital and print letter editions can be quickly and easily searched
according to sender, addressee, writing location, and date.
Digital Indexes of Letters
The web service correspSearch is based on digital letter indexes that are
available online and written in the Correspondence Metadata
Interchange (CMI) Format.
The CMI format was developed by the TEI Correspondence SIG as well, and makes
a standardized comparison of letter metadata possible. It does this by
reducing the index to only the most essential elements—the sender,
addressee, date, and location of a letter—as well as by regulating the
inputted data. In addition to the benefits of TEI-XML encoding,
standardization is greatly aided through authority files. Sender, addressee,
and location are identifiable independently of the specific project (for
example, through the GND
number from the German National Library) and the data can be
searched, linked and used outside of a particular project. Finally, in CMI
the individual letter is referenced by the letter identification number or
through bibliographical information for print editions and by the URL for
The data behind the web service is an ever growing collection of digital
letter indexes provided by print or digital scholarly editions of letters.
The web service does not set limitations regarding the historical time
period or place. A list of the letter indexes that are currently in the web
service data base can be found in the data
The database of the web service is continually being extended. Any print or
digital scholarly letter edition may register their index of letters in the
CMI format through the correspSearch web service.
Please note that scholarly editions of letters generally only focus on the
correspondence of one person or between two persons. Other letters (for
instance a letter between two family members of the main correspondent of an
edition) are in the rule only considered with regard to the main
correspondent. In addition, the data might be incomplete, either because not
yet all of the letter indexes at hand are integrated, or because the
respective edition is not yet finalized. Furthermore, the correspSearch web
service only considers letters that are part of a scholarly edition. Letters
which have not been published are not considered by the web service at this
Web Service Features
The web service offers one website through which one can search and research
within multiple letter editions using their digital indexes. The indexes are
available online under a free license from their respective hosts and their
data is regularly retrieved and updated by the web service. Every index
simply needs to be registered through a URL and will then be automatically
When processing the indexes the authority files of correspondents will be
used to query the Virtual International Authority File (VIAF) system for
other existing authority files, so that different identification systems can
be used together. Currently the web service supports GND, VIAF, the
Bibliothèque nationale de France (BNF), the Library of Congress (LC), and
the National Diet Library (NDL) in Japan. The geographical data base GeoNames is used for place
The aggregated letter indexes are searchable by correspondent, location, and date. Correspondent
and location can be specified according to their role in the communication
process. It is also possible to search within a particular letter index.
Search results disiplay the metadata of the individual letter, together with
biographical details. Letters from digital editions are directly linked to
their original source.
In addition to the website, multiple technical interfaces are available with
which the web service can be automatically queried. Results are outputted in
CMI format (among other options) and are thus free for further use by other
The Berlin Brandenburg Academy of Sciences and Humanities is, with its 25
academy projects and various third-party funded projects, the largest
non-university research institute for the humanities in the
Berlin-Brandenburg region. Besides the TELOTA research group the BBAW is
also home, for example, to the Digital Dictionary of the German
Language (Digitale Wörterbuch der deutschen Sprache) and the German Text
Archive (Deutsches Textarchiv).