It also records that eight varieties of pearls accompanied Prince Vijaya's embassy to the Pandyan king as well as king Devanampiya Tissa's embassy to Emperor Ashoka. Pliny the Elder (23–79AD) praised the pearl fishery of the Gulf as most productive in the world. For thousands of years, seawater pearls were retrieved by divers in the Indian Ocean in areas such as the Persian Gulf, the Red Sea and the Gulf of Mannar. Evidence also suggest a prehistoric origin to pearl diving in these regions. Starting in the Han Dynasty (206 BC–220 AD), the Chinese hunted extensively for seawater pearls in the South China Sea, particularly in what is now Tolo Harbour in Hong Kong. Tanka pearl divers of twelfth century China attached ropes to their waists in order to be safely brought back up to the surface. When Spanish conquistadors arrived in the Western Hemisphere, they discovered that around the islands of Cubagua and Margarita, some 200 km north of the Venezuelan coast, was an extensive pearl bed (a bed of pearl oysters). One discovered and named pearl, La Peregrina pearl, was offered to Philip II of Spain who intended to give it as a gift for his daughter on the occasion of her marriage, but the King found it so beautiful that he kept it for himself. Later, he elevated it to be part of the Spanish Crown Jewel. From then on, the pearl was recorded in every royal inventory for more than 200 years. According to Garcilasso de la Vega, who says that he saw La Peregrina at Seville in 1607, this was found at Panama in 1560 by a slave worker who was rewarded with his liberty, and his owner with the office of alcalde of Panama. Margarita pearls are extremely difficult to find today and are known for their unique yellowish color. Before the beginning of the 20th century, pearl hunting was the most common way of harvesting pearls. Divers manually pulled oysters from ocean floors and river bottoms and checked them individually for pearls. Not all mussels and oysters produce pearls. In a haul of three tons, only three or four oysters will produce perfect pearls. British Isles Pearls were one of the attractions which drew Julius Caesar to Britain. They are, for the most part, freshwater pearls from mussels. Pearling was banned in the U.K. in 1998 due to the endangered status of river