It has already been stated that Las Casas was the first to urge the substitution of African for Indian slavery, and as early as 1517 such a measure was authorized by the crown. The natives lacked the physical strength needed to meet the demands of their taskmasters, and negroes from the Portuguese settlements on the coast of Guinea were largely imported into the Spanish West Indies. Numbers of them were driven by ill-usage to take refuge in the forests and mountain fastnesses, where they led a nomadic life or made common cause with the natives, and when attacked by the Spaniards neither gave nor accepted quarter. About the middle of the sixteenth century the woods in the vicinity of Nombre de Dios swarmed with these runaways, who attacked the treasure-trains on their way across the Isthmus, defeated the parties sent against them by the governor of the province, and lurked in wait for passengers, assailing them with poisoned arrows, and cutting into pieces those who fell alive into their hands. Organized as marauding companies they became widely known as _cimarrones_[XXII‑1] or Maroons as they were called in Jamaica and Dutch Guiana. At times they would unite their forces and ravage a wide extent of country, leaving ruin on every side. Houses were burned, plantations destroyed, women seized, merchandise stolen, and settlers slain. Such was the attendant terror that masters dared not chastise their slaves, nor did merchants venture to travel the highways except in companies of twenty or more.[XXII‑2] In the year 1554 many hundreds of them were thus banded in Tierra Firme alone. About this time the new viceroy of Peru, Andrés Hurtado de Mendoza, marqués de Cañete, opportunely arriving at Nombre de Dios from Spain, en route for his capital, resolved on the subjugation of these outlaws. Not long before his arrival, Pedro de Ursua, a brave and distinguished soldier, had taken refuge from his enemies in the province of Cartagena, where he had founded the city of Pamplona and made discoveries. The viceroy, believing Ursua to be unjustly persecuted and recognizing his eminent fitness, authorized him to raise troops and march against the offenders. Accordingly Ursua equipped upward of two hundred men, and set out from Nombre de Dios. The cimarrones had mustered under Bayano,[XXII‑3] a man of their own race, of singular courage, who had been elected king by those occupying the mountains between Plagon and Pacora, and whose number now exceeded six hundred.