Final answer:
The Spanish landed in Florida to protect their Caribbean empire and prevent other European powers from using the region as a base for piracy. The successful establishment of St. Augustine in 1565 solidified Spain's claim, helped by alliances with Native Americans and the defeat of the French at Fort Caroline.
Step-by-step explanation:
The Spanish made their first landing on the North American mainland in Florida primarily due to strategic interests and troublesome dynamics with neighboring powers. Florida's position allowed Spain to protect its Caribbean interests and form a barrier against other colonial powers. In 1513, Juan Ponce de León claimed the land for Spain, naming it Pascua Florida. Despite initial setbacks, the establishment of St. Augustine in 1565 secured Spain's presence in the region.
The French attempted to weaken Spain's hold by building Fort Caroline, but Spain quickly eradicated this threat, reaffirming their control. The Spanish forged relations with indigenous peoples through missions, and San Agustín (St. Augustine) not only became a site of cultural exchange but also the oldest continuously settled European settlement in the continental United States. The strategic importance of Florida manifested as it provided a base of operations for Spain amid threats from the English and French and served as a haven for Native American allies and escaped enslaved people.