This is called monogamy as opposite to polygamy (multiple spouses at the same time).
Answer:
Reconquista, English Reconquest, in medieval Spain and Portugal, a series of campaigns by Christian states to recapture territory from the Muslims (Moors), who had occupied most of the Iberian Peninsula in the early 8th century.
Explanation:
They invested in a lot of human capital and fortified their military.
Entering the United States.
