The Byzantine Empire refers to the wide time period spanning the 4th century up to the mid-15th century. It was also alternately known as the Eastern Roman Empire. Byzantium was the earlier capital of the Roman Empire. The 4th century Roman Emperor Constantine built a new administrative capital to the east, on the Bosphorus river, called Constantinople. Byzantine architecture mostly developed during the rule of Justinian I, in the 6th century. The empire under Justinian I was spread around the Mediterranean sea, covering a large periphery. The expanse of the empire reduced, later limiting to the areas covering present-day Greece and Turkey. It is said that Justinian carried forward Constantinople's perspective in bringing up religious structures. There are also similarities found in the early Christian architecture and the Byzantine styles. Basilicas formed the most common structural similarities, along with the use of apse, mosaic, and clerestory. Architects in the Byzantine Empire have borrowed heavily from Roman temples, combining the best of all designs. Apse: Semi-circular termination of the main building, or the hemispherical end of the nave. Nave: Central part of a church from the entrance to the chancel or altar. Clerestory: Walls rising high, above the height of the roof, with windows to allow light to penetrate. The construction functioned primarily on two types of plans: basilican or axial, and the circular or central plan. However, different styles of building evolved in the later period, especially after the invention and use of pendentives in the dome structures. Byzantine structures can be identified by their peculiar domes. Theses huge hemispherical roofs used to be based over a square-shaped foundation. The construction of one heavy design over another required immense detailing and perfection. To achieve this, two techniques were resorted to: 1. Use of the squinch. This is like an arch in every corner of a square base, that transforms it into an octagon, or 2. Use of the pendentive. This is known to be a revolutionary breakthrough in the Byzantine architectural style. It is almost like a triangular segment of a spherical surface. These segments fill up all the upper corners of a room. Therefore, they form a strong circular support at the base of a dome. Pendentives were utilized to form a circular dome over a square room, or an elliptical dome over a rectangular room. This peculiar design evolves from the mix of the symmetrical central plan and the conventional basilica or axial plan. Churches shaped like the cruciform were constructed with this unique foundation. It was built over a square-central mass, with four arms spread out at equal lengths. This 11th century style or plan included five elements, four in the corners and the fifth one placed above it. This was the highlight of the Greek-cross architecture. The Holy Apostles in Thessaloniki, Athens, is an example. ◆ Lofty and towering interior spaces, with rich and luxurious decoration. ◆ The columns were made of marble, and displayed beautiful inlay work. ◆ Vaults of the structure were never left empty, mostly filled with various mosaics. ◆ The ceilings were sometimes coffered using gold. ◆ Byzantine structures, mostly the churches, had stone pavements. The early period of this architectural style refers to the old structures built during the rule of Justinian I. Many of these ancient edifices still stand proudly in Ravenna and Istanbul. The Hagia Sophia (or the Ayasofya in Turkey) built in Constantinople, is the epitome of Byzantine architecture. Another heritage structure, the Basilica of Sant'Apollinare Nuovo in Ravenna, reflects the typical longitudinal structure, common to a basilica. ◈ Church of St Sophia, Bulgaria ◈ San Vitale Ravenna, Italy A radical change in the architectural style of this empire came about during the reign of Justinian I. His architects invented a different system that brought about the transfer of the earlier square plan of building to a circular plan. So, the structures built henceforth usually featured domes supported by pendentives. Some works during this transitional or developmental phase include the Hagios Demetrios in Thessaloniki, Athens, Saint Catherine's Monastery on Mount Sinai, in Egypt, and Jvari Monastery in present-day Georgia. Here are some famous architectural marvels from the Byzantine era. The Holy Apostles of Constantinople in Istanbul, the Cattolica di Stilo in southern Italy built in the 9th century, the Sangarius Bridge, and the Karamagara Bridge are a few of them. ◈ Hagia Sophia, Sophia, Bulgaria ◈ Hagia Irene in Istanbul, Turkey ◈ Hagia Sophia in Trabzon, Turkey ◈ Holy Apostles in Thessaloniki, Athens ◈ Virgin Mary Holding the Christ Child ◈ Ancient Byzantine Mosaic The Romanesque and Gothic styles of architecture are influenced by the Byzantine construction pattern. Romanesque architecture also considers the structural walls or piers (wall sections) to be the main load-bearing segments. Cathedrals in France and Italy show small influences in their structural plans or decoration styles. Also, Islamic architecture on the eastern side of the Mediterranean has peculiar attributes originating from the Byzantine style. Dome of the Rock, built around 691 AD in Jerusalem is a striking example. The Umayyad Mosque of Damascus built in the early 8th century is similar to the Christian basilicas, but with further modifications. ◈ Dome of the Rock, Jerusalem Westminster Cathedral in London is an example of Byzantine culture being revisited through buildings. In the 1800s, industrial buildings showcased the Bristol Byzantine style in Bristol, which was a combination of Byzantine and Moorish architecture. It was developed to a greater extent by Russian architects. The temple of Saint Sava in Belgrade is a 12th century marvel, and the biggest neo-byzantine structural attempt. A centrally planned Greek-cross design, it has a large dome resting on four pendentives, and semi-domes built over apses. ◈ Westminster Cathedral in London ◈ Alexander Nevsky Cathedral in Sofia, Bulgaria The designs of the Alexander Nevsky Cathedral in Sofia, St Volodymyr's Cathedral in Kiev, St. Mark's Church in Belgrade, St. Nicholas Naval Cathedral in Kronstadt, and the New Athos Monastery in New Athos near Sukhumi are all influenced by Byzantine art.