Palatine Chapel, Aachen

The plan and decoration of the building combines elements of Classical, Byzantine and Pre-Romanesque, and opulent materials as the expression of a new royal house, ruled by Charlemagne.

The building he designed has a simple exterior and a complex interior, with a double shell octagonal dome resting on heavy piers, a two-story elevation, and elaborate revetment[5] and decoration.

In 936 Otto I, the first Holy Roman Emperor of the Ottonian dynasty, took advantage of the chapel's close association with Charlemagne and held his coronation as King of Germany there.

In that year he wrote to Pope Hadrian I and requested "mosaic, marbles, and other materials from floors and walls" in Rome and Ravenna, for his palace.

The construction, including barrel and groin vaults and an octagonal cloister-vault in the dome, reflects late Roman, or Pre-Romanesque, practices rather than the Byzantine techniques employed at San Vitale, and its plan simplifies the complex geometry of the Ravenna building.

The bronze decoration is of extraordinarily high quality, especially the doors with lions heads and the interior railings, with their Corinthian order columns and acanthus scrolls.

The inscription above the ground floor archer reads: "CUM LAPIDES VIVI PACIS CONPAGE LIGANTUR INQUE PARES NUMEROS OMNIA CONVENIENT CLARET OPUS DOMINI, TOTAM QUI CONSTRUIT AULAM EFFECTUSQUE PIIS DAT STUDIIS HOMINUM QUORUM PERFECTUI DECORIS STRUCTURA MANEBIT SI PERFECTA AUCTOR PROTEGAT ATQUE REGAT SIC DEUS HOC TUTUM STABILI FUNDAMINE TEMPLUM QUOD PRINCEPS CAROLUS CONDIDIT ESSE VELIT".