CUPOLA - The steeple domes found on most Orthodox churches. There may be one cupola or as many as thirteen. One dome predominates and represents Christ as the head of the Church. On the roof of Orthodox churches are usually found one or more cupolas (towers with rounded or pointed roofs), called crests or summits.
One cupola signifies Christ, the sole head of the Christian community; three cupolas symbolize the Most-Holy Trinity; five cupolas represent Christ and the four Evangelists; seven cupolas symbolize the Seven Ecumenical Councils which formulated the basic dogmas of the Orthodox Church, as well as the general use in the Church of the sacred number seven; nine cupolas represent the traditional nine ranks of Angels; and thirteen cupolas signify Christ and the Twelve Apostles.
A peculiar feature of Russian Orthodox churches is the presence of onion-shaped domes on top of the cupolas. In the early history of the Russian Church, especially in Kiev, the first capital, the domes of the churches followed the typical Byzantine rounded style, but later, especially after the Mongol Period, Russian churches tended toward the onion domes, which, in many places, became quite stylized. Historians are not in agreement as to the origin of this particular style, but some point to the possible influence of Persia on this peculiar feature of Russian church architecture, while others argue that since this style was more popular in the far North of Russia, it had a practical application, in that the shape was particularly suited to shed the large amounts of snow common in the region.
Every cupola, or where there is none, the roof, is crowned by a Cross, the instrument of our salvation. The Cross may take one of many different shapes, generally according to the national tradition of a particular local Church. In the Russian Church, the most common form is the so-called three-bar Cross, consisting of the usual crossbeam, a shorter crossbeam above that and another, slanted, crossbeam below.