The focus shifts from the East represented by the Byzantine tradition, to the west, which is based on Roman architectural forms specifically the basilica. Central to Rome is the Holy Roman Empire. The church is divided between the East and West. The Roman Empire is divided between the East and West. Power over the church and over the monarchy becomes centralized in Rome. The seat of power keeps shifting and various different capitals for the Holy Roman Empire arise, which is where style also emanates from.
The central part of Europe is Northern Italy. Furthermore, the Romanesque style is an intertwining of Roman architecture and architecture of the church. The Church is the central driver of society all throughout the medieval period during which the Romanesque and Gothic styles are active. Buildings become a representation of what the church is bringing to the people. Money coming into the economy is also flowing into the church.
The Chapel of Charlemagne in Aachen, takes influence from Roman architecture combined with Byzantine architecture and creates a new style. Charlemagne is the first Holy Emperor crowned at the end of the 8th century and continues into the 9th century. This chapel is approximately based on Ravenna (centrally focused church). Charlemagne visited Ravenna many times and shipped materials like mosaics and marble to Aachen to build this chapel. The interior has classical columns and a number of elements were based off of Roman original designs including marble columns. Moreover, one can see the small stones making up the curve of the arch with a central key stone in the middle. These are perfectly semicircular arches, the boldness of the arch is reminiscent of romanesque style. The centrally focused interior dome itself is covered with mosaics. The mosaics used throughout the interior use a coloured marble that provides a rich colourful interior which is reflective of Byzantine style. The atrium contains an entrance with equal space on every side. The Basilica has a central nave and two aisles sometimes more on either side of the nave. The central nave has higher ceilings than the aisles. At one end of the building there is an apse. As this form becomes more developed one can see a cross section near the apse or closer to the centre of the building which has transept that allows more light in the building.
https://www.realmofhistory.com/2015/10/01/aachen-cathedral-an-enigmatic-masterpiece-signifying-the-end-of-dark-age-in-europe/
The Basilican form becomes the norm for churches in the Western part of the church. The centrally focused church stays with the Eastern part of the church. The Basilican form was civic in nature for Rome, predominantly reserved for the court or the market. There was no pagan connotations which is why Christians adopted it.
The church at San Miniato, Florence Italy, is one of Italy’s most beautiful Romanesque churches. The base has round arches, a higher ceiling with a central nave and lower roofs on aisles on either sides. The high ceiling in the centre directs one down the centre of the building and on either side of the nave are arcades. The columns are classical, likely material was borrowed from other Roman buildings. The ceiling beams form a flat ceiling with a peaked roof. The half round apse focuses the attention on the altar.
The wooden frame in conjunction with the keystone in the centre of the arc act to stabilize the arch. This is central to Roman tradition for arch buildings. A series of attached arches is termed as the arcade. If one takes the arch and overlaps these then one gets a barrel vault. Two barrel vaults crossed with one another become a groin vault.
The Durham Cathedral starts in the 11th century and evolves to include Gothic elements. The interior has heavy round arches that make up the arcade to separate the nave from the side aisles. Geometric patterns are carved in like a chevron. This is specific to Romanesque style. Columns are heavy and ornately decorated. Windows come into light the ceiling, one can see the clear story window. Furthermore, the opening lets one into the mezzanine to circulate light on the upper level, the triforium. Below the triforium the arcades open the space to the side aisles.
Durham Cathedral – Image courtesy of smarthistory.org
Durham Cathedral
In France, the Church of Saint Etienne depicts a transition from the Romanesque style into the Gothic style. There is still round arches in the arcade. The triforium has a larger opening that replicates the arch below. Above that in the clear story are small windows to light the upper portion of the building. There are no heavy columns, instead there is cluster columns that provide a lighter visual appeal. The ribbing runs from the bottom of the column to the ceiling and continues into the vaulting on the ceiling. The groin vault on the ceiling allows more space for the window on top. Thus a strong sense of erectness is created without a roof structure.
https://www.britannica.com/place/Saint-Etienne-church-Caen-France
Information courtesy of New York School of Interior Design “Historical Styles 1” class