The Incas began their history as one of several tribes that lived together on the Andean altiplano, around the present-day city of Cuzco to the north and Lake Titicaca to the south. According to Peruvian historian Valdemar Espinoza Soriano, the Inca were harassed by the Aymara from the south, which led them to flee northwards. This is how they founded the city of Cusco, at the beginning of the 13th century, around a swamp that today replaces the Plaza de Armas. However, this did not bring them peace; they had to face constant battles with neighbouring ethnic groups, among them the Ayarmacas and the Chanca.

It was with the coming to power of a certain Pachacútec, and after the victory to which he led a multi-ethnic alliance in the war against the Chanca confederation, around 1438, that the Inca began their expansion. The ninth ruler of this people – the first to refer to himself as monarch with the term ‘Inka’ was Inca Roca, who lived during the second half of the 14th century – he was succeeded by his son, the tenth Inca Amaru Inca Yupanqui. He, like the eleventh Inca Túpac Yupanqui and, finally, the twelfth Inca Huayna Cápac, continued this expansion – without entering here into internal struggles for power – until reaching what was the largest empire in pre-Columbian America, before its final annihilation in 1533, with the Spanish conquest.

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This is the stage of a century known as the Inca Empire. During this period, either because of the knowledge they assimilated from the incorporated peoples or because of the knowledge they themselves acquired, the Inca civilisation reached the peak of its culture, technology and science. One of the manifestations of this culture, technology and science was precisely their architecture.

Masonry in Inca architecture

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The Incas developed three main styles of masonry in their constructions and buildings:

Pirca style: this is made up of walls built with small and medium-sized stones, joined with adobe mortar. This is a rustic style, the most commonly used, by the way, as it allowed for easy and quick construction. It was used on mountainside terraces and in common buildings.

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-The “cellular” style, according to the term coined by the Peruvian architect Santiago Agurto: it is made up of the buildings built by the Incas with medium-sized stones carved in a polygonal shape.

Imperial style: this is the most refined style, perhaps the most unique of the Incas, with large rectangular or polygonal blocks that were carved, polished and assembled with such exquisite precision that no visible mortar was required.

McKay Savage - CC BY 2.0

Inca architecture in the imperial style brought something new to the history of architecture – the millimetric precision with which the blocks of stone were carved and then assembled like a puzzle – and it is no coincidence that it is the most admired and best known. It was mainly used for monumental buildings or buildings of functional or symbolic importance, whether they were defensive, administrative or religious constructions.

Bronze and copper tools, hammers and abrasives were used to carve, adjust and polish the granite, basalt or limestone blocks. Other elements used in construction were earth or stone ramps to lift the large ashlars into position, and plant fibre ropes to carry them. However, the humbler Inca buildings were erected with small ashlars and even adobe bricks, in the pirca or cellular style. In any case, trapezoidal shapes in windows and thresholds, and gabled roofs, are characteristic features of Inca architecture.

Diego Delso - CC BY-SA 4.0

Inca construction methods and social organisation

The construction of Inca architecture, especially public buildings in the imperial style, required an extraordinary amount of work. The system that made this possible was known in Quechua as mit’a; in Spanish, mita. It was a form of labour tribute to which Inca citizens were obliged. Under this system, all able-bodied citizens worked for the state for a certain number of days each year.

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In this way, the Inca government was able to mobilise thousands of workers for the construction of large-scale projects. It is said, for example, that the fortress of Sacsayhuaman in Cuzco took up to 20,000 men over the 50 years it took to build. The mita not only supported the construction of fortifications, temples and administrative buildings, but also served for work on roads, bridges, aqueducts and terraces.

Diego Delso - CC BY-SA 4.0

Urban planning and symbolism in Inca architecture

The Incas called their territory Tahuantinsuyo, which in Quechua means “country of the four regions”. One of the Inca’s main urban planning works, apart from the architecture itself, which is a major achievement, was the Qhapaq Ñan (or Capac Ñan, in other words. “main road”). It was a network of roads of more than 30,000 km that linked and connected the towns and cities of these four regions through an inner axis in the highlands and an outer axis on the coast, from north to south. It was inscribed as a UNESCO World Heritage Site, in the category of cultural itinerary, in 2014.

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On the other hand, it is said that the original urban design of the capital of the Inca empire, the city of Cusco – also a World Heritage Site since 1983 -, the work of Pachacútec, is in the shape of a puma, an animal sacred to his people. On the feline’s chest was the central square Haucaypata and its head rested on the hill on which the fortress of Sacsayhuamán stands. Machu Picchu, for its part, bears witness to an urban planning dictated by astronomical observation, aligned in windows and temples with celestial events such as the solstices and equinoxes.

Diego Delso - CC BY-SA 4.0

In this respect, it is necessary to clarify that the Inca invested the Sun (or Inti), one of the most important gods, as a divinity, but also the Moon (Mama Quilla), protector of women, the Earth (Pacha Mama), divinity of agricultural fertility, the lightning (Illapa), god of war, as well as many other elements of nature. This is why the integration of technology with nature, as well as architecture and urban planning, is evident in all the infrastructures they built.

Marco Antonio Ochante Martínez - CC BY-SA 4.0

One of these major infrastructures, in addition to those already mentioned, was the complex system of canals and cisterns that supplied cities and agricultural fields. The hydraulic system that extends under Machu Picchu, with underground channels that ensured a constant flow of water by gravity and drainage to prevent flooding, is a clear example.

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Origins of Inca architecture

As for their origins, some archaeologists say that the Incas were influenced by two previous cultures: the Tiahuanaco and the Huari. According to Venezuelan architect Graziano Gasparini, the Incas were inspired by the ancient city of Tiahuanaco, from which they took techniques such as the cutting and polishing of stone blocks and double jambs. However, how this tradition was maintained during the 300 years between the collapse of Tiahuanaco and the rise of the Inca is a matter of debate. Some experts suggest that the technique survived in the Lake Titicaca region, from where it was borrowed by the Inca.

Sources: Wikipedia 1, Wikipedia 2, Wikipedia 3, Wikipedia 4, Wikipedia 5, Wikipedia 6, World History Encyclopedia, MayaIncaAztec, TCS World Travel.

Images: Wikipedia.