The systematic collection of biographical data of the knight brethern of the Teutonic Order began in the 19th century. The first catalogue of knight brethren was published by Leonid Arbusow the Elder in the Yearbook of Baltic Genealogy, Sphragistics and Heraldry in 1901. In addition to personal articles, Arbusow published an introduction to the administration of the Livonian branch of the Teutonic Order and the dynamics of its personnel, as well as a table of the Order's officials and their terms of office. Together with the additions published in 1910, Arbusow's work remained for a long time the only reference to the Order's brethren.
Calls for the socio-historical study of the Teutonic Order had been heard since the 1960s. In connection with this, it became topical again to supplement and expand the necessary database, which was carried out under the auspices of the Baltic Historical Commission. Klaus Conrad, Lutz Fenske and Klaus Militzer developed the questionnaire, which they presented in 1987 and which was applied in the catalogue of the Brethren of the Order (Die Ritterbrüder im livländischen Zweig des Deutschen Ordens) published in 1993. In addition to those already mentioned, personal articles in the catalogue were compiled by Bernd U. Hucker, Wolfgang Irgang, Johannes A. Mol, Sonja Neitmann, Kurt Niederau and Hans G. Trüper. Uwe Grieme helped to compile the table of the officials of the Order.  
While Arbusow's main merit was to compile the first list of brotethren known from Livonia on the basis of Livonian sources, the great contribution of the 1993 catalogue was the identification and presentation of the family backgrounds of the brethren of the Order. The members of the Order were studied by region of origin, for example, Johannes A. Mol concentrated on the Netherlands and Klaus Militzer on the Rhineland, Cologne, Hesse, etc., when writing entries of the brethren. More extensive additional research in the archives was not undertaken, but in the case of some regions, it was possible to rely on earlier work, such as the doctoral thesis of Sonja Neitmann in the case of the County of Mark of Westphalia.  
In the intervening years, further archival research has brought more to the ranks of the Order's brothers. It has also been possible to exclude some of the names earlier listed in the catalogue because of the new information.  For the time being, the database here contains only the positions and terms of office of the brethren of the Order. Above all, it is a handy tool for identifying anonymous brethren of the Order in the sources, but it also allows to analyse the career patterns of the brethren. 

The database lists the knight brethren of the Teutonic Order who served in Livonia and their careers. Most data derives from the catalogue published by Lutz Fenske and Klaus Militzer in 1993; information on the brethren’s origins has been omitted for the time being. The list and career data have been corrected and supplemented.