quality:correction, linguistic:voice_change
Expansion and consolidation

Pachacuti had named his favorite son, Amaru Yupanqui, as his co-ruler and successor. However, as co-ruler Amaru showed little interest in military affairs. Due to this lack of military talent, he faced much opposition from the Inca nobility, who began to plot against him. Despite this, Pachacuti decided to take a blind eye to his son's lack of capability. Following a revolt during which Amaru almost led the Inca forces to defeat, the Sapa Inca decided to replace the co-ruler with another one of his sons, Túpac Inca Yupanqui. Túpac Inca Yupanqui began conquests to the north in 1463 and continued them as Inca ruler after Pachacuti's death in 1471. Túpac Inca's most important conquest was the Kingdom of Chimor, the Inca's only serious rival for the coast. Túpac Inca's empire then stretched north into what are today Ecuador and Colombia.Túpac Inca's son Huayna Cápac added a small portion of land to the north in what is today Ecuador. At its height, the Inca Empire included modern-day Peru, what are today western and south central Bolivia, southwest Ecuador and Colombia and a large portion of modern-day Chile, at the north of the Maule River. Traditional historiography claims the advance south halted after the Battle of the Maule where they met determined resistance from the Mapuche.

This view is challenged by historian Osvaldo Silva who argues instead that it was the social and political framework of the Mapuche that posed the main difficulty in imposing imperial rule. Silva does accept that the battle of the Maule was a stalemate, but argues the Incas lacked incentives for conquest they had had when fighting more complex societies such as the Chimú Empire.

Silva also disputes the date given by traditional historiography for the battle: the late 15th century during the reign of Topa Inca Yupanqui (1471–93). Instead, he places it in 1532 during the Inca Civil War. Nevertheless, Silva agrees on the claim that the bulk of the Inca conquests were made during the late 15th century. At the time of the Inca Civil War an Inca army was, according to Diego de Rosales, subduing a revolt among the Diaguitas of Copiapó and Coquimbo.

The empire's push into the Amazon Basin near the Chinchipe River was stopped by the Shuar in 1527. The empire extended into corners of what are today the north of Argentina and part of the southern Colombia. However, most of the southern portion of the Inca empire, the portion denominated as Qullasuyu, was located in the Altiplano.

The Inca Empire was an amalgamation of languages, cultures and peoples. The components of the empire were not all uniformly loyal, nor were the local cultures all fully integrated. The Inca empire as a whole had an economy based on exchange and taxation of luxury goods and labour. The following quote describes a method of taxation:

For as is well known to all, not a single village of the highlands or the plains failed to pay the tribute levied on it by those who were in charge of these matters. There were even provinces where, when the natives alleged that they were unable to pay their tribute, the Inca ordered that each inhabitant should be obliged to turn in every four months a large quill full of live lice, which was the Inca's way of teaching and accustoming them to pay tribute.