Dr. Isaak Volmar

Isaak Volmar was the leading plenipotentiary from the Emperor when Trauttmansdorff was not present; and since Trauttmansdorff was only at the congress from November 1645 to July 1647, Volmar played a relatively significant role in the negotiations.
In 1615, Volmar entered the service of the branch of the Habsburg family that ruled Further Austria, which included the territory in Alsace that was in dispute at the Congress of Westphalia. Although he also represented Ferdinand III, therefore, Volmar was more committed to retaining Alsace than the Emperor’s own preferences would have dictated. His intimate understanding of the complicated administrating situation in Alsace made him particularly suited for the negotiations, but, ironically, may have contributed to France’s gaining more than they otherwise would have.
Volmar was raised a Protestant, but converted to Catholicism as an adult. His diary is a major source for the negotiations.
Books
The Imperial Privy Council in the Seventeenth Century (1943) by Henry Frederick Schwarz (Harvard Historical Studies, vol. 53).
“Über den Zusammenhang von Verhandlungstechnik und Vertragsbegriffen. Die kaiserlichen Elsaß‑Angebote vom 28. März und 14. April 1646 an Frankreich” (1998), by Konrad Repgen, in Dreißigjähriger Krieg und Westfälischer Friede, ed. by Franz Bosbach and Christoph Kampmann, 643–676.
“Die jüngere tirolische Linie bei den Westfälischen Friedensverhandlungen. Zur Geschichte der Feindschaft zwischen Isaak Volmar und Wilhelm Bienner” (1969) by Adam Wandruszka, in Neue Beiträge zur geschichtlichen Landeskunde Tirols: Festschrift zum 70. Geburtstag von Franz Huter, 445–453 (Tiroler Wissenschaftsstudien, vol. 26).