A few days later, however, the Spaniards took fright at the approach of a fleet of a hundred praus, cut their cables and hoisted their sails. They were pursued by one or two of the native boats, but they soon beat these off with their guns. In attacking these vessels they captured a number of prisoners, some of whom they released; retaining, however, nineteen Malays (three of them women) for the purpose of taking them to Spain.[34] [34] Some of these (including the women) were set free in the Moluccas, others died on the voyage, but a few actually did reach Seville, and with one exception, after being carefully instructed in Christianity and the Spanish language, were sent back to the Philippines in 1527. The exception was a Malay who showed himself so extraordinarily clever about money matters and trade that the Spaniards feared if he returned to the Far East he might be a little too knowing in appraising the value of European trade goods. So he apparently ended his days in Spain. As to the Malay junks or ships with which they had now come into contact, Pigafetta writes an interesting description. The hull of the vessel was built of planks fastened together with wooden pegs, the carpentry being very clever and neat; but at a height of about 15 inches above the water level the construction was continued with large bamboos. The masts were of bamboo and the sails were of bark cloth, or palm-leaf matting. North Borneo, like the Philippines, had long been semi-civilized by intercourse with China. All well-to-do people possessed porcelain dishes and cups, and the Muhammadan Malays used bronze money impressed with Chinese characters. The Bornean Malays had a curious habit of taking small doses of mercury (quicksilver), not only to cure illnesses, but in the belief that it prevented sickness by purging the body. Pigafetta also relates that the Sultan of Brunei possessed two pearls as large as hens' eggs, so round, however, that they would not stand still on a table. These pearls came from the south-western islands of the Philippine archipelago. They had belonged to the king of the principal island of the Sulu archipelago, whose daughter had married the Sultan of Brunei, and had unwisely boasted of her father's pearls as big as hens' eggs. Her husband determined to get possession of them, by force if necessary, so had assembled a fleet of 500 praus (or, as another variant of the story puts it, 50), and sailing by night he surprised the King of Zolo, or Sulu, and two of his sons, and carried them off to Brunei, where he held them as captives until the pearls were delivered to him.