Italian City States
Cathedral of Pisa
The increased trade and competition among the cities led to a rapid increase in architectural production, and to an experimentation with new forms. Particularly important was the introduction of stone vaulting.
To support the vault, the building could have decided to build thicker walls, but instead they interpreted the side aisles as structural buttresses for the vault, transforming the interior of the building into a tripartite space visually coordinated with the vaults over the aisles.
One of the earliest churches built in the new manner is the Speyer Cathedral, begun around 1040, with the vaulting completed around 1137.
The nave elevation of Speyer was defined by series of high arches mindful of a Roman aqueduct. Window at the top bring light into the nave.
Even more significant was the presence of a single attached column that rose from the floor to the base of the vault, some 32 emters from the floor, higher than any other vault at the time. The tall proportion allow the building to seem more compact and controlled, and to some eyes, more Roman, especially when compared to Hildesheim`s static arrangement of volumes.