Тhe authors of the article return to the topic of the history of a well-known Tatar clan of Tobolsk servicemen Kulmametev. The article is based on the documents found in regional and central archives. Particular attention is paid to the analysis and reasoned criticism of recent publications on the topic, which challenge the conclusions of the authors of this article about the origin, status of clan representatives in the XVII century, which are crucial not only for the history of a particular clan, but also for understanding the whole history of Siberian service Tatars. The revealed archival materials confirm that the family descends from Prince Begish of the Siberian Khanate and that Kulmametevs' ancestors enjoyed a high status and became leaders of the service Tatars in the late 17th century.