Some characteristics of Islamic architecture were inherited from the pre-Islamic architecture of that region while some characteristics like minarets, muqarnas, arabesque, Islamic geometric motifs, pointed arch, multifoil arch, onion dome, and pointed dome developed later.
THE ISLAMIC GARDEN
Shalamar Gardens is a typical Mughal paradise garden in Lahore. Gardens and water have for many centuries played an essential role in Islamic culture, and are often compared to the garden of Paradise. The type originates from the Achaemenid Empire. In his dialogue "Oeconomicus", Xenophon has Socrates relate the story of the Spartan general Lysander's visit to the Persian prince Cyrus the Younger, who shows the Greek his "Paradise at Sardis". The classical form of the Persian Paradise garden, or the charbagh, comprises a rectangular irrigated space with elevated pathways, which divide the garden into four sections of equal size:
One of the hallmarks of Persian gardens is the four-part garden laid out with axial paths that intersect at the garden's centre. This highly structured geometrical scheme, called the chahar bagh, became a powerful metaphor for the organization and domestication of the landscape, itself a symbol of political territory.
A Charbagh from Achaemenid time has been identified in the archaeological excavations at Pasargadae. The gardens of Chehel Sotoun (Isfahan), Fin Garden (Kashan), Eram Garden (Shiraz), Shazdeh Garden (Mahan), Dowlatabad Garden (Yazd), Abbasabad Garden (Abbasabad), Akbarieh Garden (South Khorasan Province), Pahlevanpour Garden, all in Iran, form part of the UNESCO World Heritage. Large Paradise gardens are also found at the Taj Mahal (Agra), at Humayun's Tomb (New Delhi), in India; the Shalimar Gardens (Lahore, Pakistan), or at the Alhambra and Generalife in Granada, Spain.
The sahn (courtyard) and minaret of the Great Mosque of Kairouan, Tunisia In the architecture of the Muslim world courtyards are found in secular and religious structures.
Residences and other secular buildings typically contain a central private courtyard or walled garden. This was also called the wast ad-dar ("middle of the house") in Arabic. The tradition of courtyard houses was already widespread in the ancient Mediterranean world and the Middle East, as seen in Greco-Roman houses (e.g. the Roman Domus). The use of this space included the aesthetic effects of plants and water, the penetration of natural light, allowing breezes and air circulation into the structure during the summer heat, as a cooler space with water and shade, and as a protected and proscribed place where the women of the house need not be covered in the hijab clothing traditionally necessary in public.
A ṣaḥn (Arabic: صحن) – is the formal courtyard found in almost every mosque in Islamic architecture. The courtyards are open to the sky and surrounded on all sides by structures with halls and rooms, and often a shaded semi-open arcade. A mosque courtyard is used for performing ablutions and as a patio for rest or gathering. Sahns usually feature a central pool or fountain to aid with ablutions, sometimes sheltered under an open domed pavilion. Historically, because of the warm Mediterranean and Middle Eastern climates, the courtyard also served to accommodate larger numbers of worshippers during Friday Prayers
A Hypostyle, i.e., an open hall supported by columns, is considered to be derived from architectural traditions of Achaemenid period Persian assembly halls (apadana). This type of building originated from the Roman-style basilica with an adjacent courtyard surrounded by colonnades, like Trajan's Forum in Rome. The Roman type of building has developed out of the Greek agora. In Islamic architecture, the hypostyle hall is the main feature of the hypostyle mosque.
One of the earliest hypostyle mosques is the Tarikhaneh Mosque in Iran, dating back to the eighth century. Some scholars refer to the early hypostyle mosque with a courtyard as the "Arab plan" or "Arab-type" mosque. Such mosques were constructed mostly under the Umayyad and Abbasid dynasties; subsequently, however, the simplicity of this type of plan limited the opportunities for further development, and as a result, these mosques gradually fell out of popularity in some regions.
In Islamic buildings, vaulting follows two distinct architectural styles: While Umayyad architecture in the west continues Syrian traditions of the sixth and seventh century, eastern Islamic architecture was mainly influenced by Sasanian styles and forms.
Qusair 'Amra vaulting In their vaulting structures, Umayyad period buildings show a mixture of ancient Roman and Persian architectural traditions. Diaphragm arches with lintelled ceilings made of wood or stone beams, or, alternatively, with barrel vaults, were known in the Levant since the classical and Nabatean period. They were mainly used to cover houses and cisterns. The architectural form of covering diaphragm arches with barrel vaults, however, was likely newly introduced from Iranian architecture, as similar vaulting was not known in Bilad al-Sham before the arrival of the Umayyads. However, this form was well known in Iran from early Parthian times, as exemplified in the Parthian buildings of Aššur. The earliest known example for barrel vaults resting on diaphragm arches from Umayyad architecture is known from Qasr Harane in Syria.
During the early period, the diaphragm arches are built from coarsely cut limestone slabs, without using supporting falsework, which was connected by gypsum mortar. Later-period vaults were erected using pre-formed lateral ribs modeled from gypsum, which served as a temporal formwork to guide and center the vault. These ribs, which were left in the structure afterward, do not carry any load. The ribs were cast in advance on strips of cloth, the impression of which can still be seen in the ribs today. Similar structures are known from Sasanian architecture, for example from the palace of Firuzabad. Umayyad-period vaults of this type were found in Amman Citadel and in Qasr Amra.
An iwan in the Jameh Mosque of Isfahan The term iwan denotes a hall that is walled on three sides and opens on one side. It is typically covered by a vault although this can vary. This feature was present in Sasanian architecture, though its exact origins are older and still debated. It was later incorporated into Islamic architecture. Its usage became more common and widespread under the Seljuks in the 10th century. Iwans were used in a variety of ways and arranged in varying positions in relation to the rest of the building. They are found in many types of buildings including mosques, madrasas, palaces, and caravanserais. One characteristic layout consists of four iwans arranged around a central square or rectangular courtyard, with the iwans aligned with the central axes of the courtyard.
For mosques and madrasas, one of the iwans could be oriented towards the qibla (direction of prayer) and include a mihrab in order to serve as a prayer space.] The related Persian term, pishtaq, is used to denote an entrance portal (sometimes an iwan) projecting from the façade of a building, often decorated with calligraphy bands, glazed tilework, and geometric designs.
Because of its long history of building and re-building, spanning the time from the Abbasids to the Qajar dynasty, and its excellent state of conservation, the Jameh Mosque of Isfahan provides an overview of the experiments Islamic architects conducted with complicated vaulting structures.
The system of squinches, which is a construction filling in the upper angles of a square room so as to form a base to receive an octagonal or spherical dome, was already known in Sasanian architecture. The spherical triangles of the squinches were split up into further subdivisions or systems of niches, resulting in a complex interplay of supporting structures forming an ornamental spatial pattern that hides the weight of the structure.
The tradition of double-shelled brick domes in Iran has been traced back to the 11th century. At the beginning of the 15th Century A.D., major Timurid monuments like the Gur-i Amir Mausoleum and the Bibi Khanum Mosque (both completed around 1404 A.D.) were notable in their use of large double-shelled domes. These domes were composed of an inner shell that was visible from the interior and a larger outer shell, visible from the exterior and often of a slightly different shape. The Gur-i Amir Mausoleum's dome, the oldest one to have survived to the present day, features an exterior ribbed profile with a band of muqarnas around its drum. However, domes of this shape and style were likely constructed earlier, as evidenced by the Sultaniyya Mausoleum in Cairo, which was built earlier in the 1350s A.D. and appears to have copied this same design from the Iranian tradition.
The "non-radial rib vault", an architectural form of ribbed vaults with a superimposed spherical dome, is the characteristic architectural vault form of the Islamic East. From its beginnings in the Jameh Mosque of Isfahan, this form of the vault was used in a sequence of important buildings up to the period of Safavid architecture. Its main characteristics are:
1. four intersecting ribs, at times, redoubled and intersected to form an eight-pointed star;
2. the omission of a transition zone between the vault and the supporting structure;
3. a central dome or roof lantern on top of the ribbed vault.
While intersecting pairs of ribs from the main decorative feature of Seljuk architecture, the ribs were hidden behind additional architectural elements in later periods, as exemplified in the dome of the Tomb of Ahmed Sanjar in Merv, until they finally disappeared completely behind the double shell of a stucco dome, as seen in the dome of Ālī Qāpū in Isfahan.