Nanyue was seen as attractive to the Han rulers as they desired to secure the area's maritime trade routes and gain access to luxury goods from the south such as pearls, incense, elephant tusks, rhinoceros horns, tortoise shells, coral, parrots, kingfishers, peacocks, and other rare luxuries to satisfy the demands of the Han aristocracy. Other considerations such as frontier security, revenue from a relatively large agricultural population, and access to tropical commodities all contributed to the Han dynasty's desire to retain control of the region. Panyu was already a major center for international maritime trade and was one of the most economically prosperous metropolises during the Han dynasty. Regions in the principal ports of modern Guangdong were used for the production of pearls and a trading terminal for maritime silk with Ancient India and the Roman Empire.