Alternation of supports

[2] An early example of technique used for a decorative purpose can be found in Hagios Demetrios, a 5th century Byzantine church in Thessaloniki.

[citation needed] There were some notable exceptions, however: for example, the lateral aisles of the Notre-Dame de Paris have alternating piers of lower and greater strength that provide a "powerful appeal to the eye and the senses", but had originally fulfilled a structural need, as the heavier piers carried an extra load from the intermediate supports in the buttress system.

Also, the alternation can be found in some early Gothic designs of sexpartite vaults, where the support for the middle transverse rib carries less load.

However, frequently the column and pier alternation was used for purely decorative purposes, most likely following the Byzantine idea found in the Hagios Demetrios.

[3] The second area of the frequent use of the alternation was Germany, with the earliest example still standing of the church of Saint Cyriakus, Gernrode (c. 960-1014).