History literally passed through Pálffy Palace. Its uniqueness and immense significance lie in the fact that within a single object it visually captures a great number of key historical and architectural stages of the city’s development. In the basement we see evidence of a Celtic settlement (oppidum) from the 1st century, including a shaft for storing food, a grave, and finds that document the close proximity of the mint. The Roman period is illustrated by the proliferation of secondary building material used in the masonry of the building – clearly visible within the preserved early medieval walls of the 13th century Romanesque palace. The core of the town's Gothic palace with a chapel featuring a star vault from the 15th century was discovered in the basement and first floor of the building during a rescue survey in 1981–1987. Parts of the masonry, also from the 15th century, can be seen in the exhibition hall on the third floor. The Slavic period left its traces in the basement, where four graves from the 9th and mid-10th centuries were discovered. Further building modifications in Neoclassical style date back to the 17th and 19th centuries.
In the 18th century the palace was acquired by the Pálffy family, and until the dissolution of the Austro-Hungarian monarchy it served them for presentational purposes. The last owner, Ján Pálffy Sr., housed part of his valuable art collection there, including historical furniture, a collection of silver objects, rare works of artistic craftsmanship, and paintings by Italian and Dutch masters. None of the items from this collection can be seen in the building today.
After the death of Count Pálffy, a philanthropist, patron, and collector of European art, the palace underwent extensive restoration, and in 1988 it became the seat of Bratislava City Gallery. The restoration revealed a remarkable stage of the palace’s medieval building history. Perhaps the most interesting find was the Gothic core of the building, which was dated to the middle of the 14th century by the entrance’s stone sedilia (niches with a seat). Many architectural elements of the early palace, as well as those of later alterations, were preserved during the last restoration and can be still seen today.