Heinrich Keil (1829–1911), a native of Opava, was an Austrian army officer that participated in the defense of Timișoara against the Hungarian army in the summer of 1849. In 1855, he was awarded the rank of knighthood for his military exploits. For his coat of arms, he selected military symbols related to the siege of Timișoara: a tower entwined with a serpent and a lion awaiting it at the top of the tower, holding a sword. In 1877, he became the owner of Turn Castle and sold it five years later. Nonetheless, in that short span of time, the castle seems to have undergone a restoration, as shown, among other things, by the family coat of arms built into it and the inscription 1878 carved in the castle tower.

Sources:
Preinfalk, Miha: Plemiške rodbine na Slovenskem, 9. in 20. stoletje. Part 3: Od Aljančičev do Žolgerjev. Ljubljana: Viharnik, 2017, pp. 100–110.