Final answer:
Pachacuti initiated the imperial expansion of the Inca Empire, conquered the Chimor kingdom, and implemented administrative reforms that facilitated the empire's growth.
Step-by-step explanation:
Pachacuti was a transformative leader in Inca history who is credited with beginning the imperial expansion of the Inca Empire in the mid-15th century. During his reign from 1438 to 1471, Pachacuti orchestrated the conquest of the Chimor kingdom and other territories, which significantly expanded the reach of the Incas.
He implemented strategies that included military conquest and diplomatic assimilation to incorporate conquered peoples into the empire, which eventually included parts of modern-day Peru, Ecuador, Bolivia, Argentina, Chile, and Colombia. Furthermore, Pachacuti reformed the administrative system, developed infrastructure like roads and storehouses, and codified a state religion, which all played critical roles in the cohesion and efficiency of the Inca Empire.