Vas County became the centre and territorial base for his future expansions and acquisitions of landholdings in all directions throughout Western Transdanubia, which elevated into a large-scale contiguous and coherent territorial province by the end of the 13th century. It was Henry, who built the castles of Szentvid and Szalónak (present-day Stadtschlaining, Austria) in the county. Receiving large-scale personal land donations for his military career and loyalty in the upcoming decades, he was the founder and first member of the Kőszegi family (formerly incorrectly also called Németújvári or Güssingi in historiography), which had dominated the northwestern part of Vas County and their lands were arranged around significant fortresses, for instance Borostyánkő (today Bernstein in Austria) and the eponymous Kőszeg, which was developed into an advanced trading town under Henry's domination, who granted town privileges to the settlement and moved his permanent residence there after a construction of a well-fortified castle. With Béla's support and generous donations, Henry Kőszegi established his lordship independently of his kinship and did not rely on the clan's formerly acquired landholdings in the opposite parts of Vas County. Henry Kőszegi and his descendants had become the dominant power of whole Transdanubia within decades, spreading from their paterfamilias' first acquired lands in Vas County. By 1270, Henry owned the forts of Kőszeg, Szentvid, Szalónak, Borostyánkő, Kertes (Pinkakertes, today a borough of Eberau, Austria), in addition to the castles of the late "Farkas of Zagorje" and possibly Léka (today Lockenhaus in Austria). However, Henry never possessed the fort of Németújvár (Burg Güssing) in his lifetime; it was regained only by his son, Ivan for the Héder clan after almost a century, in the early 1280s. Thus the earlier Hungarian historiographical efforts to call the family as "Németújváris" or "Güssingis" (and also "Küszinis") is unfounded and anachronistic; nevertheless, they are still appear as "Güssingers" in German-language academic works. In contemporary records, they were referred to as "generacio Heyderici" (1265) or "genus Heydrich" (1279).
