The principal edifice of Łazienki is the Palace on the Isle (). It was originally a baroque Bath-House erected in about 1680 by Lubomirski according to the design of Tylman van Gameren, the most outstanding architect in Poland at that time. The square-shaped structure had a three-side protrusion on its northern elevation. Inside was a round hall with a fountain and the hall was topped by a cupola illuminated from above by lanterns. The walls were studded with pebbles, seashells and imitated grotto. Adjoining it was a bath chamber with walls adorned by bas-reliefs. Both the building's interior as well as its exterior elevation were richly decorated with stucco, sculptures and murals. A portion of the original decorations survived on the entrance wall of the columned portico. Also original is the Latin inscription to be read as a rebus. In translation, it states: “This house hates sorrow, loves peace, offers a bath, recommends an idyllic life and wishes to play host to honest men.”