This is a guide to the archival collections of the Saxe-Coburg-Gotha dynasty housed in the Royal Archives at Windsor Castle and in the State Archives at Coburg and Gotha. It includes all documents which offer insight into the history of British-German relations. Material from the lifetimes of Prince Albert (1819-1861) and Queen Victoria (1819-1901) has received particular attention and been given more detailed treatment. In the Royal Archives the earliest documents date from the late seventeenth century and the most recent are from the 1940s. The documents from Coburg span the period from the late eighteenth to the twentieth century, while the earliest documents from Gotha date from the sixteenth century and the most recent from the twentieth. Extensive indices show the considerable connections between the collections. The publication is the product of the research project »Common Heritage: the Collections of Windsor and Coburg«. A second volume will document the historic libraries and photographic collections.