Inventory of Microfilm Reels T-17425 to T-17429: Intercepted Vichy and Free French Diplomatic Telegrams (1941–1945) — Library and Archives Canada, RG24-C-22

This dataset provides a structured inventory of five microfilm reels held at Library and Archives Canada (LAC) under Record Group RG24-C-22 (MIKAN 134683), covering intercepted diplomatic telegraphic traffic produced and processed during the Second World War (September 1941 – July 1945). The reels span two distinct series of intercepted communications: Vichy French diplomatic traffic (message series prefixed D) and Free French diplomatic traffic (message series prefixed FG), both intercepted and processed by Canada’s Examination Unit (XU) — the country’s first civilian signals intelligence and cryptanalysis bureau, established in 1941 under the National Research Council.

The inventory was compiled as part of the Canadian Vichy Intercepts project at the University of Ottawa, a digital humanities initiative building an AI-assisted pipeline to transcribe, structure, and publish approximately 13,848 digitized pages from these reels. The primary source for the reel-level metadata is the LAC finding aid document 24-171 (Reel/Bobine T-17425 – T-17429).

Each row in the dataset corresponds to a distinct record series within a reel. Note that reel T-17427 contains two separate record series (one Free French, one Vichy French), and therefore appears in two rows.

The dataset is designed to serve as a persistent, citable reference inventory linking physical archival objects (microfilm reels) to their intellectual content (message series, date ranges, and digitized image sequences). It is intended to support researchers working with the corpus on the project’s Omeka Classic platform (https://omeka.uottawa.ca/examination-unit/) as well as those conducting independent archival or historical research.

Historical Context

The Examination Unit was created in June 1941 under the direction of Herbert O. Yardley and later Norman Robertson, operating under the aegis of the National Research Council and in close collaboration with Britain’s Government Code and Cypher School (GC&CS) at Bletchley Park and the U.S. Army Signal Intelligence Service. Its primary mandate was to intercept and decrypt foreign diplomatic and military communications, with French traffic — both Vichy and Free French — forming a substantial portion of its workload from 1941 onward.

The intercepted telegrams in reels T-17425 to T-17429 represent a primary source corpus for understanding Canadian signals intelligence operations and Allied knowledge of French diplomatic activity during the Second World War. The reels are organized chronologically and by traffic type, covering the full operational period of French diplomatic intercept work at the XU (September 1941 – July 1945).

Files

Filename
Format
Description

microfilms_reels.csv
CSV (UTF-8)
Structured inventory of the five microfilm reels and their record series

Data Dictionary

microfilms_reels.csv

Column
Type
Description
Example

rg
String
Record Group identifier at Library and Archives Canada
RG24-C-22

reel
String
Microfilm reel identifier (LAC call number)
T-17425

traffic_type
String
Type of diplomatic traffic intercepted. Controlled vocabulary: Free French (FG) or Vichy French (D)
Free French

message_prefix
String
Alphabetic prefix of the message numbering series for this reel/traffic combination
FG

message_number_from
String
First message number in the series (inclusive), including prefix
FG3861

message_number_to
String
Last message number in the series (inclusive), including prefix
FG7117

date_from
Date (ISO 8601)
Start date of the date range covered by this record series (YYYY-MM-DD)
1944-10-01

date_to
Date (ISO 8601)
End date of the date range covered by this record series (YYYY-MM-DD)
1945-07-31

image_from
Integer
Sequence number of the first digitized image on this reel/series (to be populated)
1

image_to
Integer
Sequence number of the last digitized image on this reel/series (to be populated)
3136

Notes on specific fields

traffic_type: The distinction between Vichy French and Free French traffic reflects the two rival French governmental authorities during the occupation period. Vichy traffic originates from the collaborationist government headquartered in Vichy; Free French traffic originates from the government-in-exile led by General de Gaulle.

message_prefix: The prefix D denotes the Vichy French diplomatic series; FG denotes the Free French diplomatic series. These prefixes appear in the original LAC finding aid and are used as identifiers throughout the project’s metadata schema.

date_from / date_to: Where the LAC finding aid provided only year-month precision (e.g., 1944-10), the first day of the month was assigned for date_from and the last day of the month for date_to, following the convention of inclusive date normalization to ISO 8601.

image_from / image_to: These columns are reserved for the digitized image sequence numbers as assigned by the project’s image identifier scheme (format: t17425_0001). Values are pending final reconciliation with the project’s structured_telegrams_v2.csv metadata file.