ndres de Pez y Malzarraga was born into a Naval tradition. Born in Cadiz, Spain in 1657, de Pez's father and older brother were Naval captains in Spain's prestigious naval guard. By the age of 16, de Pez had entered the naval guard and spent most of his early career aboard escort vessels cruising to and from the wild frontiers of the Americas.

In 1676, at the battle of Palermo, de Pez witnessed the deaths of his brother and father at the hands of the French. With a consuming hatred for all things French, young de Pez persevered, becoming a company commander in the Armada de Barlovento, the famed "Windward Fleet" of the Caribbean Sea and Gulf of Mexico which was charged with guarding Spanish ships and colonies from foreign attackers and pirates.

Fighting French pirates in the Caribbean he earned a reputation for "outstanding bravery and efficiency." On one occasion, pirate forces were so substantial that 65 of de Pez's men were killed and de Pez himself was wounded five times. Because of his emonstrated courage and daring, the Count of Monclova selected de Pez to explore the largely unmapped coasts of the northern Gulf of Mexico with the goal of locating and destroying a rumored French colony established by Sieur de La Salle. He participated as second in command on three of these voyages between 1688 and 1689.

La Salle's abandoned colony was located in that year (in present day Texas); however, de Pez had begun developing a plan to establish a stronghold in the northern Gulf to keep the French out of the "Spanish Sea" for good. He needed a deep-water bay that could be easily defended from approach with land that would be good for a fort and town. De Pez, had heard a glowing account of just such a place from Juan Enriquez Barroto who had drawn a cursory map from a voyage in 1685. Though de Pez was never able to enter Pensacola Bay during his 1688 voyages, he did view it from the Gulf and became convinced that the place was far superior to Mobile Bay to the west.

Pez sailed to Spain to convince the War Council of the need to abandon St. Augustine and establish a stronghold along the shores of Pensacola Bay.
Though the story of de Pez's attempts to gain favor (as well as men and money) for his plan is detailed, suffice to say that de Pez faced great opposition from powerful men and exhibited a mastery of cunning and diplomacy which eventually resulted in gaining support from the King himself. This support took the form of funds for an official reconnaissance of the bay, and a promotion to the rank of admiral. Admiral de Pez returned to New Spain (Mexico) in the fall of 1692 and began plans for the expedition that would lead to the first successful European colonization of Pensacola.

De Pez sailed from Veracruz on March 25, 1693 taking with him Capt. Juan Jordan de Reina and the pre-imminent scientist and cartographer Don Carlos de Siguenza y Gongora. They carried with them 120 sailors and 20 infantrymen in two ships: the frigate, Neustra Senora de Guadalupe, and the sloop, San Jose. The expedition entered the bay on April 7. Siguenza named the bay Bahia Santa Maria de Galve.

They landed on Punta de Siguenza - the west end of Santa Rosa Island - and after an elaborate ceremony led by Siguenza, erected a cross there and buried a man who had died on the journey, Antonio Lopez, at the base of the cross. Inspection of the bay was undertaken for nine days during which time Siguenza took detailed soundings and mapped the area all the way to the Blackwater and East Bay Rivers. The former river was given the name Rio del Almirante in honor of Admiral de Pez.
The results of this expedition and both de Pez and Siguenza's strong recommendations led eventually to the founding of the Presidio Santa Maria de Galve in 1698 along the shores of Pensacola Bay.

Andres de Pez had developed the plan, lobbied the highest officials of Spain for support, and had commanded the expedition that sealed the fate of Pensacola
Unfortunately, he could not see his plan to fruition. His skill and expertise as a defender of Spanish shipping made him indispensable to the Spanish Navy. He commanded the entire Windward Fleet until 1701, and then served in increasingly higher positions of administrative and judicial powers.

During the War of the Spanish Succession, he fought the Catalán rebels who refused to accept the Bourbon prince Philip as their monarch, and served as captain­general of the Indies fleet from 1708 to 1710. Pez was received in 1715 as a member of Spain's Supreme War Council. In 1717 he was named governor of the Council of the Indies. He was named secretary of state and navy in 1721. Protector of women, children, and Spanish gold on the high seas; a master seaman and explorer - pirates feared him and Kings sought his council; "death came . at half past four in the afternoon, to the most excellent lord Don Andres de Pez,,," in Madrid, Spain on May 7, 1723.