Final answer:
The Moors dominated Spain from the 8th century until 1492 when they were defeated by the Catholic Monarchs. The Reconquista shaped the military and religious character of Spain and paved the way for its role in the era of Atlantic exploration, colonization, and spreading of Catholicism.
Step-by-step explanation:
The nationality that dominated Spain from the 8th century until it was defeated in 1492 is C. The Moors. The Moors, consisting of North African Berbers, Mid-Eastern Arabs, and other Muslim peoples from Morocco, conquered the Iberian Peninsula in 711 A.D. and ruled until the completion of the Reconquista.
The Reconquista was a series of campaigns by Christian states to recapture territory taken by Muslims. In 1492, the last Moorish stronghold, Granada, was conquered by the Catholic Monarchs, Ferdinand II of Aragon and Isabella I of Castile, thus ending Moorish rule in Spain.
To put this historical period into context, the Portuguese and Spanish were major players in the era of Atlantic exploration, with Spain initiating this era. Portugal, notable for its maritime tradition, established the first colonies in the Americas.
These Iberian powers were both involved in the Reconquista and benefited from the 1494 Treaty of Tordesillas, which split the newly discovered lands outside Europe between the Spanish and the Portuguese along a meridian 370 leagues west of the Cape Verde islands.
Following the defeat of the Moors, Spain continued to grow as an imperial power. This growth was complemented by the spread of Roman Catholicism through missionary work in the New World, which plays a significant role in Spain's legacy.