For ten points, name this empire that ruled much of Western South America in pre-Columbian times.
One legend about this empire's origins speaks of how its ruler fled the capital in terror before a siege while his son remained and defeated the besiegers. One of the final rulers of this empire dreamt of thousands of foreigners (*)  on an empty battlefield just before his death, which precipitated a civil war between his two sons. Descendants of this empire's royalty included Garcilaso de la Vega, and this empire was sometimes named for the four administrative  suyus that it was divided into. The Lord of Cajamarca was a major power broker in this empire, as was the Lord of Quito. For ten points, name this empire that ruled much of Western South America in pre-Columbian times.
One legend about this empire's origins speaks of how its ruler fled the capital in terror before a siege while his son remained and defeated the besiegers.
Inca  (accept  Tawantinsuyu  or "Empire of the four Quarters" before "suyu")