The age of military power and of the cultural renaissance of the Byzantine Empire opens with the reign of Basil I. The smooth functioning of institutions, peace within the Church, and competent emperors of the Macedonian dynasty contributed to an effective defence of the Empire against the Bulgarian threat.
After the death of Basil II the Empire entered upon a period of peace, but also of gradual disintegration. At the same time, Byzantine civilisation of that period was being shaped by a flowering of intellectual life, the conversion of neighbouring peoples to Christianity, and monastic organisation, as well as by the development of internal economic structures.
The ravaging of the Byzantine Empire by the Franks (1204) was preceded by barbarian incursions beginning in the 11th century, revolts by Byzantine office-holders, Bulgarian revolutions and the founding of the second Bulgarian state at the end of the 12th century, and the Norman wars (1081-1185) -- all coincident with ineffectual emperors and the gradual collapse of the economy and administration.