The article presents the figure of Wilhelm Kögler – a little known Prussian archaeologist. The earliest reference to the activities of Kögler comes from 1904. In his monograph of the cemetery at Mojtyny (Moythienen), Emil Hollack, author of research, thanks Kögler for his cooperation of many years (E. Hollack, F. Peiser 1904, p. 3). A year later, in 1905, Kögler, former forestry worker, presumably without much formal education, was employed by the Prussia-Museum. His work involved helping to sort the collections and assisting “the gentlemen who run the excavations” (General-Versammlung 1919, p. 507). From that time on Kögler is mentioned in the journal Prussia as a participant of excavations (F. Peiser 1916, p. 1; 1919a, p. 295; 1919b, p. 354–355). Many more details are provided by the archival documentation from excavations made by the Prussia-Museum, held at present by the Museum für Vor- und Frühgeschichte in Berlin. It follows from these papers that Kögler participated in most excavations run during the first decades of the 20th century in Masuria, working with Emil Hollack, Felix Peiser and Max Ebert. Kögler appears, in the background, in a number of photographs of the investigated sites (Fig. 1–3). On occasion, he made visits, on his own, to newly identified sites or carried out preliminary studies. This suggests he had the knowledge necessary to date the discovered materials and establish their culture attribution. Among sites in the investigation of which Kögler was a participant we need to name Spychówko (Kl. Puppen), Koczek (Koczek), Onufryjewo (Onufrigowen), Miętkie (Mingfen), Mojtyny (Moythienen), Suśnik (Susznik), Gęsiki (Meistersfelde), Braniewo-Podgórze (Braunsberg-Huntenberg), Marcinkowo (Mertinsdorf) and Dłużec (Langendorf). But we have reason to believe that this list is far from complete. In the written documentation there is no mention whatsoever that Kögler was involved in the fieldwork at Gąsior (Jaskowska-See/Gonschor) but he definitely appears in photographs taken during the investigation made of this cemetery. The references to Kögler’s activities continue until 1926, after which they are no more. Analysis of reports from the fieldwork at Gąsior and Onufryjewo in which Kögler took part leads to the conclusion that documentation was made at lightning speed – a few dozen features were explored every day (Table I), plotted against the grid square, their depth below the ground level recorded and their general description given, at times, complete with a drawing of the cinerary urn. There is no doubt that F. Peiser who ran the investigation would not have been able to cope with such a task while he was also keeping his eye on the diggers. Apparently, his assistant who was responsible for the excavation even on the days when Peiser was not in the field was none other than Wilhelm Kögler. He must have been indispensable to Peiser as assistance for, in 1915 when WW I was in progress, the drafted Kögler was given leave from the army to carry out an excavation at Piastowo (Pajki) with Peiser. Another relevant conclusion is that fieldwork continued not only on the days when the site documentation was kept and this has obvious consequences for the reliability of its results. Thus, we may say that the excavation activities of Kögler, who mostly remains in the background, definitely contributed to the progress of Prussian archaeology. Through the neglect of “the gentlemen who run the excavations” he was forgotten for more than a hundred years. But he deserves praise, nevertheless.