What is the cause of the feud between the families of Ulrich von Gladwitz and George Znaeym?
Like many others, the feud between Ulrich von Gladwitz and Georg Znaeym has been inherited from ancestors, and the lines of demarcation are so ambiguous that there is no resolution to this generations' argument over a tract of land. Here is how the narrator describes this feud as Gradwitz patrols the dark forest:
A famous law suit, in the days of his grandfather, had wrested it from the illegal possession of a neighbouring family of petty landowners; the dispossessed party had never acquiesced in the judgment of the Courts, and a long series of poaching affrays and similar scandals had embittered the relationships between the families for three generations.
In other words, Gradwitz's grandfather had gone to court to "wrest" this land away from Znaeym's grandfather; however, the Znaeyms did not acknowledge the ruling of the court. So, now each family insists that the land is theirs, and they continue to hunt upon it. Resentment between the two parties waxes and the hatred becomes personal between Gradwitz and Znaeym so that the feud is aggrandized. This is why Gradwitz hopes one night that he can singularly come upon his enemy and kill him. But, just as comes around a tree, he comes vis-à-vis with Znaeym. Fatefully, however, in that "long silent moment" in which two civilized men cannot just shoot down someone down, a great tree splits in the storm and branches crash upon them. And, while they are thus pinioned beneath the tree and wait for their men to rescue them, it is only then that they put this feud into true perspective.
One family stole some of the other families land.