- The cellars were constructed together with the main building in 1334 and are the only parts of the building that have survived to the present day in their original historical form.
- The cellars once served as a storage area used by merchants. The brotherhood's wine reserves and treasures brought by merchants, such as grain, leathers, flax, honey, wax, and other goods, are said to have been stored here.
- In order to ensure that the premises stayed warm in the colder months of the year, a warm air heating system, also known as a hypocaust, was built, which can be found in the historical part of the building.
Nowadays, visitors can familiarise themselves with the history of the Brotherhood of the Black Heads by engaging in educational activities in the cellars.