The Inca Empire was a kingdom that developed in the Andes region of South America and gradually grew larger through the military strength and diplomacy of their emperors. Known as Tawantinsuyu, the Inca state spanned the distance of some 2,500 miles, from northern Ecuador to central Chile, and at its peak consisted of 12 million inhabitants from more than 100 different ethnic groups. Well-devised agricultural and roadway systems, along with a centralized religion and language, helped maintain a cohesive state. Despite their power, the Inca were quickly overwhelmed by the diseases and superior weaponry of Spanish invaders, and the last bastion of their immense empire was overtaken in 1572.
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Inca Empire Begins
The Inca first appeared in modern-day Peru sometime during the 12th century, arising from earlier pre-Inca groups in the region. These earlier groups have been credited with creating the ancient Nazca Lines, immense drawings etched into the landscape.
According to some versions of their origin myths, they were created by the sun god, Inti, who sent his son Manco Capac to Earth through the middle of three caves in the village of Paccari Tampu. After killing his brothers, Manco Capac led his sisters and their followers through the wilderness before settling in the fertile valley near Cusco.
The Inca began expanding their land holdings by the reign of their fourth emperor, Mayta Capac. However, they did not truly become an expansive power until the eighth emperor, Viracocha Inca, took control in the early 15th century.
Bolstered by the military capabilities of two uncles, Viracocha Inca defeated the Ayarmaca kingdom to the south and took over the Urubamba Valley. He also established the Inca practice of leaving military garrisons to maintain peace in conquered lands.
When the rival Chancas attacked circa 1438, Viracocha Inca retreated to a military outpost while his son, Cusi Inca Yupanqui, successfully defended Cusco.
Cusi Inca Yupanqui — who soon took the title Pachacuti — became one of the Inca’s most influential rulers. His military campaigns extended the kingdom to the southern end of the Lake Titicaca Basin, and hundreds of miles north to subject the Cajamarca and Chimu kingdoms.
The expanding reach of the Inca state — now called Tawantinsuyu or “Land of the Four Quarters” — prompted strategic logistical considerations. Pachacuti is believed to have been the first Inca emperor to order forced resettlement to squash the possibility of an uprising from one ethnic group.
In addition, Pachacuti established the practice in which rulers were prevented from inheriting the possessions of their predecessors, thereby ensuring that successive leaders would conquer new lands and accumulate new wealth.
Pachacuti also focused his efforts on strengthening Cusco, the government center of the vast empire. He expanded Sacsahuaman, the massive fortress that guarded the city, and embarked on an expansive irrigation project by channeling rivers and creating intricate agricultural terraces.
Although Tawantinsuyu was comprised of more than 100 distinct ethnic groups among its 12 million inhabitants, a well-developed societal structure kept the empire running smoothly.
Most Inca subjects were self-sufficient farmers who tended to corn, potatoes, squash, llamas, alpacas and dogs, and paid taxes through public labor.
There was no written language, but a form of the Quechua language became the primary dialect, and knotted cords known as quipu were used to keep track of historical and accounting records.
The Inca are today celebrated for many artistic and cultural achievement, including their monumental architecture, of which the magnificent fortress complex Machu Picchu is but one example.
The Inca also developed sophisticated calendars, elaborate textiles, functional and decorative ceramics, surgical techniques, productive terrace agriculture and the use of coca leaves as medicine and in religious ceremonies. They also practiced mummification of their dead.
An elaborate system of roadways adding up to approximately 15,000 miles crisscrossed the kingdom, with relay runners capable of advancing messages at the impressive rate of 150 miles per day.
Unfortunately, many of the gold and silver creations of the Inca were melted down by Spanish conquistadors and sent back to Europe.
The Inca religion centered on a pantheon of gods that included Inti; a creator god named Viracocha; and Apu Illapu, the rain god. Impressive shrines were built throughout the kingdom, including a massive Sun Temple in Cusco that measured more than 1,200 feet in circumference.
Powerful priests depended on divination to diagnose illness, solve crimes and predict the outcomes of warfare, in many cases requiring animal sacrifice. The mummified remains of previous emperors were also treated as sacred figures and paraded around at ceremonies with their stores of gold and silver.
Upon ascending to the throne in 1471, Topa Inca Yupanqui pushed the southern border of the empire to the Maule River in modern-day Chile, and instituted a tribute system in which each province provided women to serve as temple maidens or brides for celebrated soldiers. His successor, Huayna Capac, embarked on successful northern campaigns that stretched the vast civilization to the Ancasmayo River, the current boundary between Ecuador and Colombia.
READ MORE: How Inca Mummies Ruled Over the Living
Despite these advances, the arrival of Spanish explorers in the 1500s soon set into motion the events that would lead to the collapse of the Inca Empire. The Spanish carried such alien diseases as smallpox and influenza, which wiped out a huge chunk of the population before killing Huayna Capac and his chosen successor around 1525.
Those two deaths sparked a civil war as would-be emperors battled for power, with Atahualpa eventually outlasting his half-brother, Huascar, to grab the throne of the now-weakened empire.
Enamored by the stories of Inca wealth, Spanish conquistador Francisco Pizarro lured Atahualpa to meeting in November 1532 for a supposed dinner in his honor — and then kidnapped the emperor. Atahualpa was executed the following summer, and although the Spanish were far outnumbered by the locals, they easily sacked Cusco in late 1533 with their superior weaponry.
Attempting to keep the peace, the Spanish installed a young prince named Manco as a puppet king, a move that backfired during a spirited rebellion in 1536. However, Manco and his men were eventually forced to retreat to the jungle village of Vilcabamba, which remained the last stronghold of the empire for about 36 years.
Eventually, however, the Spaniards took control of Vilcabamba in 1572, when the last remaining Inca ruler, Manco’s son Tupak Amaru, was captured and executed, bringing the Inca Empire to an end.
As the only written accounts of the Inca were composed by outsiders, its mythology and culture passed to successive generations by trained storytellers.
Traces of its existence were mainly found in the ruins of cities and temples, but in 1911 archaeologist Hiram Bingham discovered the intact 15th century mountaintop citadel of Machu Picchu, its magnificent stone structures reflecting the power and capabilities of this proud and powerful pre-Colombian civilization.
WATCH: Engineering an Empire on HISTORY Vault
Rise of the Inca. NOVA. PBS.
From Chavin to the Inca, a Timeline of the Central Andes. The British Museum.
The Last Days of the Incas. Kim MacQuarrie; Simon & Schuster.
The Inca and Machu Picchu. Smithsonian Associates.