Note: every manifestation of a letter is counted, so the number of documents in a repository may be larger than the number of letters.

Repository Number of documents Further details
Accademia dei Concordi 1 Alternative names for repository: Biblioteca dell' Accademia dei Concordi
City: Rovigo
Country: Italy
Alnwick Castle Collections and Archives 2 City: Alnwick, Northumberland
Country: England
Archive du Ministère des Affaires Etrangères 3 City: Paris
Country: France
Archive of the Russian Academy of Sciences 93 Alternative names for repository: Archive of the Academy of Sciences Archiv der Akademie der Wissenschaften (AAN) Sankt-Peterburgski˘ı filial Arkhiva Rossi˘ısko˘ı Akademii Nauk Archive of the Russian Academy of Sciences, Petersburg Branch St Petersburg Branch of the Russian Academy of Science’s Archive PFARAN
City: St Petersburg
Country: Russia
Archives de l'État 1 Alternative names for repository: Archives de l'État en Belgique Rijksarchief in België State Archives of Belgium Archives générales Archives générales du Royaume
City: Brussels
Alternative names for city: Bruxelles
Country: Belgium
Archives départementales du Puy-de-Dôme 1 City: Clermont-Ferrand
Country: France
Archives municipales 2 City: La Rochelle
Country: France
Archivio dei Gonzaga di Castiglione delle Stiviere 12 Alternative names for repository: Archivio di Stato
City: Mantua
Country: Italy
Archivio della Pontificia Università Gregoriana 2361 Alternative names for repository: Pontificia Università Gregoriana Archive Archives of the Pontifical Gregorian University
City: Rome
Country: Italy
Archivio di Stato di Firenze 13 Alternative names for repository: State Archive of Florence
City: Florence
Alternative names for city: Firenze
Country: Italy
Archivio di Stato di Lucca 4 City: Lucca
Country: Italy
Archivio Histórico Municipal de Valencia 4 City: Valencia
Country: Spain
Archivum Romanum Societatis Iesu 13 Alternative names for repository: The Archives of the House of the Superior General
City: Rome
Alternative names for city: Roma
Country: Italy
Archiwum Państwowe w Gdańsku 4 City: Gdańsk
Alternative names for city: Danzig
Country: Poland
Archiwum Państwowe w Poznaniu 64 Alternative names for repository: Archivum Państwowe w Poznaniu Archivum Państwowe AP
City: Poznań
Alternative names for city: Posen
Country: Poland
Archívum Magyar Országos Levéltár 5 Alternative names for repository: National Archives of Hungary
City: Budapest
Country: Hungary
Arhivele Statului Sibiu 1 City: Sibiu
Country: Romania
Arundel Castle Archives 13 City: Arundel, West Sussex
Country: England
Arxiu Nacional de Catalunya [ANC] 2 Alternative names for repository: Archivo Nacional de Cataluña ANC National Archive of Catalonia
City: Barcelona
Country: Spain
Ashmolean Museum 2 City: Oxford
Country: England, United Kingdom