The former Biesiadecki Palace (also formerly owned by the Bielski, Potocki, and Komorowski families; currently housing a library) was built in the early eighteenth century. It underwent major changes over the years: a reconstruction in 1756 by architect Pierre Ricaud de Tirregaille; an interior renovation in the 1820s by architect Fryderyk Bauman; and a further reconstruction in 1934 by architect Jan Bagieński. The architectural styles include Rococo, Empire (in the interior), and Neoclassicism.
This standalone building is set back within the property behind a garden, which is separated from the square by a stone wall with an entrance gate. It is a prime example of eighteenth- and nineteenth-century urban palace architecture. Despite various renovations, the monument has preserved its original structural core.