religion and language of their conquerors. European powers fight over Puerto Rico 16th century Puerto Rico was considered the "Key to the Caribbean" by the Spanish because of its location as a way station and port for Spanish vessels. In 1540, with revenue from Mexican mines, the Spanish settlers began the construction of Fort San Felipe del Morro ("the promontory") in San Juan. With the completion of the initial phase of the construction in 1589 El Morro became the island's main military fortification, guarded by professional soldiers. The rest of Puerto Rico, which had been reorganized in 1580 as the Captaincy General of Puerto Rico, had to rely on only a handful of soldiers and the local volunteer militia to defend the island against militant and pirate attacks. The main enemies of Spain at the time were the English and the Dutch. They, however were not the only enemies that Spain faced in the Caribbean during this period. On October 11, 1528, the French sacked and burned the settlement of San Germán during an attempt to capture the island, destroying many of the island's first settlements—including Guánica, Sotomayor, Daguao and Loiza—before the local militia forced them to retreat. The only settlement that remained was San Juan. In 1585, war broke out between England and Spain—extending to Spanish and English territories in the Americas. In November 1595, Sir Francis Drake and Sir John Hawkins attempted an unsuccessful invasion of San Juan. On June 15, 1598, the English fleet, led by George Clifford, landed in Santurce and held the island for 157 days. He was forced to abandon the island upon an outbreak of bacillary dysentery among his troops, losing 700 men to the outbreak. On December 26, 1598, Alonso de Mercado, a military man was named to the Captaincy General of Puerto Rico by Spain and asked to punish anyone who had allowed the takeover, through negligence, malice or cowardice. 17th century The Dutch Republic was a world military and commercial power by 1625, competing in the Caribbean with the English. The Dutch wanted to establish a military stronghold in the area, and dispatched Captain Boudewijn Hendricksz (also known as Boudoyno Henrico or Balduino Enrico) to capture Puerto Rico. On September 24, 1625, Enrico arrived at the coast of San Juan with 17 ships and 2,000 men. Enrico sent a message to the governor of Puerto Rico, Juan de Haro, ordering