Here are short descriptions of the development of each architectural styles as well as its most significant elements. The text contains references to the most famous architects and buildings of each period.

In the first century before christ there already exist some predecessors of the romanic churches. An example for this is an underground basilica in front of the Porta Maggiore in Rome. The simplest way to cover an area using only round arches is the barrel vault. Two opposite walls are linked with a surface built of one round arch next to the other. One of the characteristics of the use of romanic arches is obvious here: The round arch is always part of a circle, so with the widening of the arch (to cover a wider area) the height of the arch increases too. To cover wide areas with romanic arches it is necessary to divide the vault into some smaller vaults standing next to each other. That way rows of pillars are needed in the interior of a large building to carry these vaults. So it is impossible to create large halls without carrying pillars standing in the inside.

Barrel vaults divide an area into multiple tunnel-like vaults. To create large, unpartitioned rooms one can intersect these tunnels in the form of a cross. That way we get a so called groined vault that makes a lighter impression but is still able to carry the weight of the roof. By building lines of these crossings a covered corridor, an arcade. Multiple arcades can form a covered hall.

A predecessing form of the later romanic churches is the roman  basilica . The basilica is the product of the attempt to build a representative multi-purpose hall with only round arches. It was used as a covered market and as courtroom. To get a large room that is still lit by the sun even in its center a higher central nave was built that has some openings in the upper part of the walls. On each side of this nave smaller aisles we built that are divided from the central nave by its pillars so that a visitor gets the impression of smaller rooms. In this way the basilica provides the suitable room for large meetings in the center as well as for more intimate conversations in the aisles.

A characteristic of the groined vault with romanic arches is that it can only cover quadratic areas. This is because the round arches from the left to the right must reach the same height of the roof as the arches from the front to the back. This quality leads to the ad quadratum principle of the basilica: The central nave is exactly twice (or three times) as wide as the small aisles so that each two (or three) arches of an aisle are covered by one large arch of the central nave. If the nave is made of 4 arches, the aisles have 8 (or twelve) of them. Often the pillars of the aisles are designed in a different form than those of the central nave (eg as columns) so we get an alternating sequence of different pillars in the central nave which is called  alternating support.