The palace is now part of the permanent exhibition of the Budapest History Museum in "Building E" of Buda Castle.
The oldest part of the present-day palace was built in the 14th century by Prince Stephen, Duke of Slavonia, the younger brother of King Louis I of Hungary.
The Gothic palace of King Louis I was arranged around a narrow courtyard next to Stephen's Tower (Budapest) [hu].
The last phase of grand-scale building activity happened under King Matthias Corvinus when Italian artists and craftsmen arrived at Buda.
The medieval palace was destroyed in the great siege of 1686 when Buda was captured by the allied Christian forces.
After the Baroque and turn of the 20th century Royal Palace of the Habsburgs was damaged in World War II archeological research was begun to unearth the remains of the medieval castle.
It came out that important parts of the former Sigismund and Matthias palace survived under the thick level of earth fill.
The rooms which were unearthed after 1946 were only saved by the chances of destruction and their geographical position, situated on a lower level then the newly created Baroque terrace.
Both the Gothic Hall and the Palace Chapel were built by King Sigismund Luxemburg in the beginning of the 15th century.
Architect László Gerő in 1958–1962 partially recreated the façades of the Gothic castle facing the narrow southern, western and eastern courts.
The unfinished state of the façade is indicated by the fact that roof is flat – the castle is simply cut in the line of the Baroque terrace above it.
One window which had been walled up was discovered in situ during the archeological research, and the others were reconstructed from fragments by sculptor Ernő Szakál by means of anastylosis.
Its reconstruction was a much debated issue because the balcony tower goes above the level of the Baroque terrace, disturbing the harmonious panorama of the palace.
The building of the Gothic Hall is connected to the Stephen's Castle (István vár) on the western side.
It was named after Prince Stephen, Duke of Slavonia, the younger brother of King Louis I of Hungary.
Only the foundation of the so-called Stephen's Tower and three interconnected, barrel-vaulted rooms survived from the original castle.
The siting of the tower was different from the later buildings and the triangle in front of it was walled up to create a continuous southern façade for the palace.
The remaining part of the Stephen's Castle (with the barrel-vaulted rooms behind) has a simple stone façade with a Gothic doorway.
It was built by King Sigismund Luxemburg of Hungary in the early 15th century as an extension of the earlier Anjou palace.
The Gothic Hall is an irregular rectangle of 20.2 x 11.55 m with a closed niche on the eastern side (the inside of the balcony tower mentioned above).
All the newly built side walls are plastered and painted white while the original stone surfaces were left uncovered.
These pieces supposedly belonged to another stately hall situated above the room but they were built into the reconstructed vaults by 20th-century restorers.
It is an interesting fact that the northern pillar of the Gothic Hall was already discovered by Alajos Hauszmann in the beginning of the 20th century.
That time the remains were buried under the outbuildings of the Royal Gardens but Hauszmann protected the medieval pillar by means of building a brick shaft around it.
The intact barrel vault of the northern room was broken by Alajos Hauszmann in the beginning of the 20th century when he filled the cellar with rubble.
The cellar was probably built by King Sigismund of Luxemburg as the Cisterna Regia i.e. the great underground cistern of the palace.
On 25 July 2007 Prime Minister Ferenc Gyurcsány chose the King's Cellar as the place to announce the list of the "most important public works projects", financed by European Union funds between 2007 and 2013.