Ottonian Architecture is an architectural style which evolved during the reign of Emperor Otto the Great (936-975). The style was found in Germany

Germany

Germany , officially the Federal Republic of Germany , is a federal parliamentary republic in Europe. The country consists of 16 states while the capital and largest city is Berlin. Germany covers an area of 357,021 km2 and has a largely temperate seasonal climate...

 and lasted from the mid 10th century until the mid 11th century.

Ottonian architecture draws its inspiration from Carolingian

Carolingian architecture

Carolingian architecture is the style of north European Pre-Romanesque architecture belonging to the period of the Carolingian Renaissance of the late 8th and 9th centuries, when the Carolingian family dominated west European politics...

 and Byzantine architecture

Byzantine architecture

Byzantine architecture is the architecture of the Byzantine Empire. The empire gradually emerged as a distinct artistic and cultural entity from what is today referred to as the Roman Empire after AD 330, when the Roman Emperor Constantine moved the capital of the Roman Empire east from Rome to...

. Apart from some examples influenced by the octagonal Palatine Chapel at Aachen such as Ottmarsheim

Ottmarsheim

Ottmarsheim is a commune in the Haut-Rhin department in Alsace in north-eastern France.-References:*...

 (11th century, Alsace) and the apse of the abbey of the Holy Trinity at Essen, religious architecture tends to diverge from the centralised plan.