Around 1250, the imperial ministers of Lauffenholtz (Laufamholz) built a residential tower on the Pegnitz (today's Unterbürger Straße 36). It is assumed that the Unterbürg manor was the ancestral seat of the Laufamholz family.
Even in the 18th century, the residence looked like a medieval moated castle, despite the early modern conversions. A drawbridge gave access to the main building. The forecourt was secured with two gates and a defensive wall. Outbuildings were grouped within the ring of walls: a habitable gatehouse at the upper gate, the castle farmhouse, a coach house, two barns, a gardener's house with attached shed, a day laborer's house, an apartment building, stables, pigsties and a bakehouse. The outer bailey was also within the pond complex, with a navigable causeway guaranteeing access.