Architect of a king's defense: dedicated to the service of the Spanish sovereign, Juan Bautista Antonelli designed innovative fortifications that still tower over the Caribbean today.

• Author: Tennant, Anne W.

ON ASH WEDNESDAY IN 1586, the English privateer Francis Drake, fresh from lucrative raiding parties in Florida and Santo Domingo, struck at Cartagena, the richest and most populous city on the Spanish Main. He effectively bypassed the small fortress of Boqueron that guarded the entrance to the inner bay and landed three thousand of his men on the sandy peninsula of Boca Grande. Only a fortified trench separated the English from the gates to the city, which, in the absence of troops or artillery, was quickly breached and a ransom of ten million pesos was soon on its way back to England. Possessing one of the most perfect natural harbors in the world, and, on her southern flank, giving access to the Magdalena River--gateway to the interior's gold and emeralds--Cartagena was of prime strategic importance to Spain's empire in the Americas. The city was the first port-of-call for Spanish ships bearing Africans destined for slavery, as well as for those vessels carrying both the luxury goods and practical merchandise coveted by the colonists. Her markets were ranted. Cartagena's chief function, however, was to defend Panama, the point of transfer for precious metals from Peru. Site had presented an alluring target for privateers and pirates for many years.

Impassioned entreaties from his subjects for protection, coupled with his own revulsion at the depredations of French, English, and Dutch corsairs in his colonial empire, convinced King Philip II that the time had come to act. He commissioned the preeminent military architect of the sixteenth century, Juan Bautista Antonelli, to perform emergency upgrades to the scanty defenses of Cartagena, but, more importantly, to survey and reassess the entire system of fortifications in the Spanish Caribbean.

By the 1580s, Spain's relations with other European nations had deteriorated markedly. Conflict with France had intensified due to enmity between Philip's father, Emperor Charles V, and King Francis I of France, bitterly resentful because the Spanish monarch had engineered his own election as Holy Roman Emperor by bribing the electors. The competing powers clashed again as the French, attracted by the wealth and future potential of America, challenged Spain's monopoly, not only by authorizing Jacques Cartier's expeditions to Canada, but also by establishing a colony in Florida that was disturbingly close to Spain's vital shipping lanes. A shaky truce soon gave way to war and Spanish ports were again fair game for French corsairs.

To make matters worse, Spain's cordial relations with England had begun to sour with each passing year of Elizabeth's reign, even though her half-sister, Many, had been married to Phillip at mid century. English merchants were granted permits by the Casa de Contratacion in Seville to operate in Spanish America, however, sharp conflicts arose over the trade in slaves and gold. When Spain ordered English ships embargoed in her ports, Elizabeth gave the royal sanction to illegal commerce, ushering in the careers of notorious privateers and pirates such as John Hawkins and Francis Drake. Privateering was a joint stock business, backed by London investors, the nobility, and, at times, the crown. Typically, four-fifths of the profits or plunder resulting from a successful voyage reverted to the financiers. At the time of Drake's assault on Cartagena, the two former allies were at war, as religious conflicts had combined with the trade impasse to produce the boiling point.

The richness of the plunder and the virtual hermetic seal placed by Spain on foreign commerce in her colonies combined to make the poorly defended cities of the Caribbean irresistible. Her enemies, France, and later, the English and the Dutch, were, above all, trading nations and they had need of the salt, hides, dyes, wood, and sugar of the Americas. Surely, news of the silver fleet, bearing treasure from Peru and Mexico, added another dimension to their cupidity.

Spotty attempts at fortifying major cities had been undertaken earlier when regular schedules and routes for the Spanish fleet were being developed, King Philip seemed more willing to finance armed convoys and coastal patrols than land defenses, which, apparently, he considered to be the responsibility of the local government and population. As a result, due to the lack of coordination, funding, durable materials, and skilled labor, the fortifications tended to be rudimentary, flimsy, and incomplete. Meanwhile, Spanish centers of wealth and shipping were prey for increasing numbers of corsairs. Belatedly, the king Acknowledged that Antonelli's sorely needed talents, plus large-scale appropriations from the royal treasury, were now indispensable for the defense of his American empire.

The Antonelli family was already well known to the kings of Spain. It was, in fact, a dynasty of military and civil engineers whose several generations served the Spanish Hapsburgs from the reign of Charles V until the...