The Story of India's Arch

The arch, as we know, is an architectural device that has been used by man since ancient times. Tthe Etruscan civilization first employed the basic principles of the arch in construction, but the Romans were the first to fully utilize the structural advantages of the true arch, vault and dome. Arches and arched openings are one of the essential elements in the vocabulary of Roman architecture. With the advent of the arch, it became possible for builders to span large openings without having to provide any intermediate supports, as it almost eliminates tensile stresses on the building materials. Managing tensile stresses had always been a problem faced by builders, as none of the common building materials used during that time were good in tension. This problem was now overcome, and massive interior spaces could be capped by vaults or domes. This system however did transmit lateral loads on the supporting piers or walls, which thus had to be adequately reinforced. 

The true arch was something that was unheard of in ancient, or even early medieval India. We do get quite a few examples of arch-like openings in the Buddhist rock cut architecture of ancient India.. None of these, however were true 'constructed' arches, applyijng the principles of arch action. They were simply openings that were 'cut out' from a single mass of rock in the shape of an arch. One of the earliest specimens of such 'arches' can be found in the Barabar Caves in Bihar (3rd centiry BC) (Fig 1.). Such openings went on to occupy a reasonably prominent position in the architrectural language of Indian rock cut architecture, as we see quite a few recurrences of such openings as it evolved through the years. The 'kirtimukh' or sun windows that are to be found in a number of the famous caves of Ajanta are in fact similar rock cut arch shaped openings.(Fig 2.) The Buddhist chaitya halls, too were covered by rock cut barrel vaults, a few brilliant examples being Caves at Ajanta.

Arch shaped openings made a complete disappearence in the Hindu architecture of India. The subcontinent was still ignorant about the structural principles and methods of construction of the true arch. Hindu architecture employed post and lintels, or corbeling in order to span openings. The post and lintel method is a basic trabeated system of spanning an opening, whereby a horizontal 'lintel' beam rests upon two vertical 'posts', thereby supporting the load above (Fig 3.). Tensile stresses once again come into play in the lower portions of the horizontal lintel, and thus limit the maximum span of the system. Corbeling involved successive overhanging courses of masonry rising up to cover the entire span (Fig 4). This method was not effective in spanning large openings either. The largest Hindu temple comlex in the world, the Angkor Vat boasts of innumerable corbeled openings(Fig), including corbeled cross vaults, but not a single arch. Hindu religious interior spaces were thus usually of a very human scale, as opposed to the monumental interior spaces that were to be found in contemporary churches and mosques.

It was in 1192 AD, with the establishement of the Delhi Sultanate, that Islam penetrated the heart of the subcontinent. And along with a new religion, came a whole new style of architecture. Islamic architecture had traditionally employed arches and domes in the construction of moques and tombs. They had the knowledge of the true arch. The arcuated style was in fact also prevelant in pre-Islam Sassanid Persia, and was thus absorbed into the architecture of the new religion.  It was in the Great Umayyad Mosque at Damascus (715 AD) that we find one of the early examples of the Muslim adaptation of the arch. With the capture of Delhi, a mosque was comissioned by the ruler Qutb ud din Aibak. This mosque was to be known as the 'Quwwat-ul-Islam' or the 'Triumph of Islam" mosque. The rulers naturally naturally expected this mosque to consist of the pointed arches and domes commonly found in the religious architecture of Islam. The local masons employed for its construction were however all Hindus, who did not have any ideas about true arch construction. So the builiders would have to create arched openings, or atleast come up with openings that would resemble the true arches that the rulers were familiar with.

The result was an unique invention. The masons continued to corbel openings as they did in Hindu temples. However, they simply chiselled the inner surfaces of the corbels, so as to externally resemble an arch.(Fig 9). These openings could never be as large as true arched openings, but the rulers were happy nevertheless. The arch shaped opening had made a reappearence in India.

The year 1280 AD was critical in the evolution of Indian architecture. It was in this year that the true arch finally made it's first ever appearence in the subcontinent. The tomb of Ghiyas ud din Balban, located in Mehrauli, Delhi, just a little way off from the Quwwat ul Islam complex became the first building in the subcontinent having true arched openings. The Indian builder had finally learnt the structural principles of arch action. The true arch had arrived in India more than 2000 years after it's first use in this world.