The establishment of a real settlement can be connected to the foundation of St. Mary's church in the castle (according to tradition, in 752) by the Longobard king Astolfo.

The church represents the primitive pole of attraction for the medieval village which was collocated, as recorded in a X century document , in "Castro Carpense".

The old castle was square and surrounded by a moat and a wooden fortress, which was later replaced by a brick wall.

The road network was based on a right-angled plan which expanded off a main road, running from north to south, which terminated at the two gates of the city walls.

The square in the centre of the castle (the actual Re Astolfo Square) was almost divided in two by St. Mary's church , called the "Sagra" after the official consecration in 1184.

Here, stood the noblemen's houses, that governed Carpi from the X century until 1331.

Then it belonged to the Pio family. Outside the walls, between the XIII and XIV centuries several small villages sprang up, to eventually become the nucleus of the future town. Between 1331 and 1525 Carpi became the permanent fieff of the Pio family (then Pio di Savoia): the city gained importance and changed its structure with new fortified buildings and later on Alberto III Pio, had his residence and the urbanistic layout rearranged, which represents the actual historical centre of Carpi.
Several buildings were added to the castle between the XIV and XV centuries not only as fortifications but also for living purposes and as such, they were richly decorated.
These features are still visible today in some parts of the Palace, in the Rocca Nuova (north wing), in the Rocca Vecchia (east wing), in the Torrione degli Spagnoli and in the Uccelliera.

The entire noble abode was transformed completely by Alberto III Pio at the end of the 1400's, beginning of the 1500's into a Renaissance styled palace.
After these alterations in 1504, the entire complex assumed the look of a real Renaissance court with the courtyard of honour in the centre, clearly a Bramante inspiration. The main element which not only changed the structureof the Pio residence but also the entire urban arrangement of the town, was the construction of the building's facade to the west, on Borgo Gioioso (the actual Piazza dei Martiri) which is the axis of the Renaissance urbanistic arrangement, replacing the Medieval layout centred around the actual Piazza Re Astolfo. When the new city wall was erected between the fourteen and fifteenhundreds the older villages were included,( i.e. the Superior village and Sant'Antonio) on the west side of the actual Piazza dei Martiri.