The massive walls rose slowly. After an enthusiastic beginning progress lagged at times for want of funds, lack of vigorous prosecution, or when epidemics thinned the ranks of slaves and Indian workmen. In the spring of 1683 it was interrupted by a threatened attack, one of many to which St. Augustine was continually subjected. English pirates landed near Matanzas Inlet, burned the Spanish outpost there, and advanced toward the capital. Warned by alert sentinels, the governor sent out a detachment of musketeers, who waited in ambush and drove the raiders back to their ships. By 1696 the great stone fort was about completed except for some of the outer work, added during later periods. Into its construction went twenty-four long years of sweat and toil beneath the Florida sun, and the lives of an untold number of slaves, Indian, and peon workmen. It was called by the Spaniards _Castillo de San Marcos_, or castle of St. Mark’s. [Illustration: _The grim walls of Castillo de San Marcos look much the same as when the stones were lifted laboriously into place._] _Settlement of Pensacola_ While the English were occupying the Atlantic Coast north of Florida, hardy French traders and explorers, including the Jesuit, La Salle, came down the Mississippi River building forts at strategic points. This threatened Florida on the west. To meet the French threat to the Gulf coast, the Spaniards under Andrés de Arriola established a fort and settlement at Pensacola in 1698, which later was to become the capital of West Florida. A previous Spanish attempt by Tristán de Luna to establish a settlement near this point in 1559 had failed. _Border Conflict_ Strife between the Spaniards in Florida and their English neighbors to the north did not at first break out into open warfare. English agents and traders began to work quietly among the border Indians, weaning some of them away from Spanish control and influence. These they then armed and encouraged to raid the Spanish Indian towns. Christian Indians captured by the English and their Indian allies were sold into slavery. Florida’s Governor Cabrera (1680-1687) complained that they even seized the “mixed ones,” children of Spanish and Indian parentage. Small bands of Yamassee Indians, then allied with the English, hovered about St. Augustine, occasionally seizing a stray Spaniard, whom they carried back to Carolina. The Carolinians even offered the Indians a reward for captured Spaniards delivered to them upon the pretense that it was to save the victims from torture.