Final answer:
The Inca engaged in a Civil War due to a succession dispute after the emperor's death and already weakened by European diseases. Atahualpa emerged victorious but weakened, allowing Spanish conquistador Francisco Pizarro to capture and execute him, leading to the Inca Empire's collapse.
Step-by-step explanation:
The Inca engaged in a civil war in the late 1520s due to the death of Emperor Wayna Qhapaq in 1528, which left the throne vacant and led to a power struggle between his sons. The devastating impact of diseases introduced by Europeans had already weakened the Inca Empire, exacerbating the chaos of the succession crisis. Atahualpa and Huáscar fought a bitter contest for the throne, which Atahualpa eventually won. However, their civil war made the Inca vulnerable to the Spanish invaders led by Francisco Pizarro.
The Inca Civil War and subsequent vulnerability combined with the arrival of the Spanish conquistadores resulted in the capture and execution of Atahualpa in 1533, marking the beginning of the end for the Inca Empire. Despite resistance attempts, such as the siege of Cuzco by Manco Inca in 1536, the Spanish imposed their rule, divided the empire, and extracted its wealth, culminating in the empire's collapse in 1535.