Why do Ulrich von Gradwitz and Georg Znaeym not get along?

The two men do not get along because they have a longstanding family feud over the overship of a specific area of land.

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.