The document provides a historical overview of Spain from Roman times to the 16th century. It discusses how the Iberian Peninsula was united under Roman rule then Christianized in the 8th century before a Muslim invasion in the 10th century. It then summarizes the Reconquest by Christian kingdoms, the establishment of separate kingdoms, and marriages that brought much of Spain under shared rulers Ferdinand and Isabella. Their rule marked Spain's rise as a great power extending across Europe and into the Americas.