Jolo lies about 4 miles from the point of intersection of latitude 6° north and longitude 121° east. It is about 540 nautical miles due south from Manila and 81 nautical miles distant from Zamboanga. The harbor is deep and free from currents. The bay is well protected on the north by the Islands of Pangasinan and Marongas and is safe from all storms except those from the northwest. Sulu occupies the most nearly central position of any island in eastern Malaysia. It lies between Mindanao on the east and Borneo on the west, and separates the Sulu Sea from the Celebes Sea. The commercial advantages of this position are unique. To the north lie the Bisayas, Palawan, Luzon, Formosa, China, and Japan; to the east Mindanao and Basilan; to the south, the Moluccas, Celebes, and Java; to the west, Borneo, Sumatra, and the Malay Peninsula. Besides, the Sulus are natural-born sailors, and their famous pearl industry has prompted them to trade since time immemorial. Their boats brought silk, amber, silver, scented woods, and porcelain from China and Japan; gold dust, wax, dyes, saltpeter, slaves, and food stuffs from Luzon, the Bisayas, and Mindanao; gunpowder, cannon, brass, copper, iron, rubies, and diamonds from Malacca and Bruney; [14] pepper and spices from Java, the Moluccas, and Celebes. Chinese merchants traded with Sulu long before the arrival of Legaspi, and while Manila and Cebu were still small and insignificant settlements Jolo had reached the proportions of a city and was, without exception, the richest and foremost settlement in the Philippine Islands. Jolo, with the exception of Bruney, had no rival in northeast Malaysia prior to the seventeenth century. Such commercial importance naturally attracted the attention of the early Spanish Governors-General and was one of the causes which led to the early invasion of Sulu. The long period of warfare which followed this invasion retarded the progress of Jolo and reduced its trade. Again, the rise of Spanish commerce in the north tended to restrict the trade of Jolo. The growth of Manila, Cebu, and Iloilo naturally diverted the commerce of Luzon and the Bisayas and the north coast of Mindanao to those cities. The later commercial decline of Jolo was probably brought about more in this way than as a result of actual clash of arms. Jolo, however, remained an important port and a transshipping station to Mindanao until a late date.