Negroes were scarce and dear in San Juan at this period, which caused the authorities to petition the emperor for permission to each settler to bring two slaves free of duty, and, this being granted, it gave rise to abuse, as the city officers in their address of thanks to the empress, stated at the same time that many took advantage of the privilege to transfer or sell their permit in Seville without coming to the island. Then it was enacted that slaves should be introduced only by authorized traffickers, who soon raised the price to 60 or 70 Castilian dollars per head. The crown officers in the island protested, and asked that every settler might be permitted to bring 10 or 12 negroes, paying the duty of 2 ducats per head, which had been imposed by King Ferdinand in 1513. A new deposit of gold had been discovered about this time (1533), and the hope that others might be found now induced the colonists to buy the negroes from the authorized traders on credit at very high prices, to be paid with the gold which the slaves should be made instrumental in discovering. But the longed-for metal did not appear. The purchasers could not pay. Many had their property embargoed and sold, and were ruined. Some were imprisoned, others escaped to the mountains or left the island. From 1536 to 1553 the authorities kept asking for negroes; sometimes offering to pay duty, at others soliciting their free introduction; now complaining that the colonists escaped _with their slaves_ to Mexico and Peru, then lamenting that the German merchants, who had the monopoly of the traffic, took them to all the other Antilles, but would bring none to this island. However, 1,500 African slaves entered here at different times during those seventeen years, without reckoning the large numbers that were introduced as contraband. Philip II tried to reduce the exorbitant prices exacted by the German monopolists of the West Indian slave-trade, but, finding that his efforts to do so diminished the importation, he revoked his ordinances. A Genoese banking-house, having made him large advances to help equip the great Armada for the invasion of England, obtained the next monopoly (1580). During the course of the seventeenth century the privilege of introducing African slaves into the Antilles was sold successively to Genoese, Portuguese, Holland, French, and Spanish companies. The traffic was an exceedingly profitable one, not so much on account of the high prices obtained for the negroes as on account of the contraband trade in all kinds of merchandise that accompanied it. From 1613 to 1621 during the government of Felipe de Beaumont, 11 ship-loads of slaves entered San Juan harbor.