From 843 onwards, architecture was dominated by the type of the cross-in-square church, which was developed gradually in the iconoclastic period, and appears in four basic variations. In this period churches were built in the architectural style of the basilica, the free cross, single-naved, triconch or tetraconch.
The ascension of Basil I to the throne in 867 saw the erection of new churches as well as the renovation of many older ones. At the same time private initiatives appeared on the part of the aristocratic class, which had started to become stronger.
A basic feature of this period is the differentiation of churches due to the materials used, in the way they were structured, their decoration and its architectural type. Thereby, Constantinople and the regions directly affected by it - Macedonia, Thrace, the seacoast of Asia Minor and a few islands such as Chios represent the school of Constantinople. On the other hand, the rest of the continental and insular Helladic territory constitutes the Helladic school.
The most usual architectural type of the school of Constantinople is the one of the complex four-columned inscribed. The churches were built using alternate layers of chiselled stones and bricks. In a few churches of the Capital, however, the unalloyed brick-masonry was applied, an extremely expensive mode of construction. As for the Helladic school its dominant architectural type was the simple four-columned along with the two-columned one. The outer structure was built using the cloisonne masonry, namely in zones of isodome stones surrounded by bricks while the surfaces were decorated with ceramoplastic jewelry.
The majority, however, of the churches representing the two schools were built in the 11th century and constituted a subject of more analytic development in the period 1025-1081.