Saint Martin's Church of Valjala is the oldest church in Estonia. Immediately after the conquest of 1227, a stone chapel was erected by Teutonic knights in Valjala not far from the ancient stronghold. Its walls form the lower part of the present church choir. On the southern side of the chapel, there was a vestry.
Soon after completion, the chapel was decorated with murals, the remaining fragments of which may be seen on the northern wall of the church (six seated apostles in a Romanesque framing). In 1240 construction of the single-nave church was started. The original chapel was transformed into a choir.
Valjala Church was robbed and partially destroyed during the St. George's Night Uprising in 1343 later reconstructed. In the second half of the 14th century, a new polygonal apse was added to the church. The tower, which is curiously located above the vestry on the southern side of the church, was probably not completed until the 17th century. In the walls of the tower, fragments of archaic trapezoidtombstones can be seen. Archaic tombstones of this type have previously only been found in western Estonia. They might originate from the pre-Conquest period.
The Kuressaare master, Nommen Lorenzen, made the altarpiece in 1820. Besides a medieval baptismal font, other noteworthy antiques inside the church are two Baroque epitaphs (of Andreas Fregius, 1664 and Gaspar Berg, 1667).
In 1888 Gustav Normann built the church's organ. The lightning struck and burned part of the roof in 1922. Dolores Hoffman, who began work on them in the 1970s, made the stained glass windows. They mark the beginning of a new tradition in Estonian stained glass art.
The most impressive elements in the interior design of the church are the high domed vaults with Westphalian ribs and bosses. A ridge in the wall and the remains of girders are evidence of a defense gallery that once ran beneath the windows of the nave. The doorway in the intrados of the chancel arch led to the loft, which served as a refuge.
The Mosque–Cathedral of Córdoba, also known as the Great Mosque of Córdoba and the Mezquita is regarded as one of the most accomplished monuments of Moorish architecture.
According to a traditional account, a small Visigoth church, the Catholic Basilica of Saint Vincent of Lérins, originally stood on the site. In 784 Abd al-Rahman I ordered construction of the Great Mosque, which was considerably expanded by later Muslim rulers. The mosque underwent numerous subsequent changes: Abd al-Rahman II ordered a new minaret, while in 961 Al-Hakam II enlarged the building and enriched the Mihrab. The last of such reforms was carried out by Almanzor in 987. It was connected to the Caliph"s palace by a raised walkway, mosques within the palaces being the tradition for previous Islamic rulers – as well as Christian Kings who built their palaces adjacent to churches. The Mezquita reached its current dimensions in 987 with the completion of the outer naves and courtyard.
In 1236, Córdoba was conquered by King Ferdinand III of Castile, and the centre of the mosque was converted into a Catholic cathedral. Alfonso X oversaw the construction of the Villaviciosa Chapel and the Royal Chapel within the mosque. The kings who followed added further Christian features, such as King Henry II rebuilding the chapel in the 14th century. The minaret of the mosque was also converted to the bell tower of the cathedral. It was adorned with Santiago de Compostela"s captured cathedral bells. Following a windstorm in 1589, the former minaret was further reinforced by encasing it within a new structure.
The most significant alteration was the building of a Renaissance cathedral nave in the middle of the expansive structure. The insertion was constructed by permission of Charles V, king of Castile and Aragon. Artisans and architects continued to add to the existing structure until the late 18th century.
The building"s floor plan is seen to be parallel to some of the earliest mosques built from the very beginning of Islam. It had a rectangular prayer hall with aisles arranged perpendicular to the qibla, the direction towards which Muslims pray. The prayer hall was large and flat, with timber ceilings held up by arches of horseshoe-like appearance.
In planning the mosque, the architects incorporated a number of Roman columns with choice capitals. Some of the columns were already in the Gothic structure; others were sent from various regions of Iberia as presents from the governors of provinces. Ivory, jasper, porphyry, gold, silver, copper, and brass were used in the decorations. Marvellous mosaics and azulejos were designed. Later, the immense temple embodied all the styles of Morisco architecture into one composition.
The building is most notable for its arcaded hypostyle hall, with 856 columns of jasper, onyx, marble, granite and porphyry. These were made from pieces of the Roman temple that had occupied the site previously, as well as other Roman buildings, such as the Mérida amphitheatre. The double arches were an innovation, permitting higher ceilings than would otherwise be possible with relatively low columns. The double arches consist of a lower horseshoe arch and an upper semi-circular arch.