inflation and a growing population made it harder to maintain colonies.
Invasion by an ambitious Alexander the Great who took over the Empire and turned it into an empire of his own.
The decline of the Inca Empire was primarily due to the arrival of Spanish conquistadors led by Francisco Pizarro in the 16th century. The Inca were vulnerable to Spanish diseases, conquered through military tactics, and weakened by internal divisions that the Spanish exploited. This ultimately led to the fall of the Inca Empire.
One thing that led to the decline of the Aztec Empire was the shortage of skilled farmers. Mistreating the people they conquered. Additionally, the Spanish Conquistadors ripped the empire apart, destroyed the Aztec Army, killed Moctezuma (the Aztec Leader), and colonized the entire region.
Francisco Pizarro. However, the Incan empire was already declining from disease brought by previous Spanish conquistadors.
The decline of the Spanish Empire was influenced by factors such as economic struggles due to costly wars, inflation, and heavy reliance on silver from colonies. Additionally, internal political instability, social unrest, and competition from other European powers also played a role in its decline.
The Aztecs had a lot of enemies and when the Spanish conquistadors arrived to Mexico the Aztec enemies were more than happy to help the Spanish destroy the Aztecs.
The most important factor leading to Alexander the Great's eventual decline was the vastness of his empire, which led to overextension and difficulty in managing such a large territory. Additionally, the lack of a clear successor and infighting among his generals after his death contributed to the fragmentation of his empire.
The period of disorder after the decline of the Roman Empire led to an extended period of disunity during the Middle Ages that was characterized by feudalism.
The short answer is: infighting and the plague.
It's takeover by Alexander the great.
The greed for land and money led to decline of Mughal Empire since more taxes were levied on peasant farmers such as the zazia tax on hindus.
Persia lost the battles of Granicus, Issus and Gaugamela, which led to Alexander's takeover of the Persian Empire.