There is historical evidence for the existence of more than 5,000 Byzantine and Venetian churches in Crete. Byzantine churches were built during the first and second Byzantine Period as well as during Venetian rule (13C to 17C). It is difficult to separate completely the Greek Orthodox from the Catholic churches. The same church may have been used for the one or the other religion at different periods, or even in the same period. In general, in the large cities, the dual nature of the Orthodox and Catholic churches is evident from the external appearance. In the countryside however, because of the vast predominance of the Orthodox population during Venetian rule, it can be assumed that the very large majority of the small churches that exist in Crete were Orthodox, with few exceptions.