to Buddhist clergies. Trade was not primarily important in Đại Việt, although Đại Việt's ceramic exports blossomed for several decades during the 15th century. Le Thanh Tong-the greatest king of the 15th century who had conquered Champa, once said "Do not cast aside the roots (agriculture) and pursue the insignificant trade/(commerce)", showcasing his unfavorable views toward trade and merchandising. Đại Việt's only single port located at the mouth of the Red River–a town called Van Don–near Ha Long Bay, was considered too far away from the main sea route. Similarly, Marco Polo also made his description of Đại Việt where he did not visit but gathered information from the Mongols: "They find in this country a good deal of gold, and they also have a great abundance of spices. But they are such a long way from the sea that the products are of little value, and thus their price is low." Most Southeast Asian and Indian merchant ships sailing along the Vietnamese coast of the South China Sea often stopped at Champa's port-cities, then bypassed Đại Việt and the Gulf of Tonkin, and headed on to southeast China. Compared to a more well-known Champa, Đại Việt was little known to the faraway world until the 16th century with the arrival of Spanish and Portuguese explorers. Medieval sources such as Ibn al-Nadim's The Book Catalogue (c. 988 AD) mention that the king of Luqin or Lukin (Đại Việt) invaded the state of Sanf (Champa) in 982. Đại Việt was included in the Arab geographer Muhammad al-Idrisi's world atlas–the Tabula Rogeriana. In the early 1300s, Đại Việt was briefly chronicled by Persian historian Rashid al-Din in his Ilkhanid annals as Kafje-Guh, which was the rendition of a Mongol/Chinese toponym for Đại Việt, Jiaozhiquo. Art and religion Buddhism had penetrated to modern-day Vietnam around the first century AD, during the Han occupation. By the 8th century, Mahayana Buddhism had become the dominant faith of the Red River Delta Region. The development of Mahayana faiths there undoubtly gave the rise for several Buddhist dynasties that would rule Đại Việt. The epigraphy of Thanh Mai inscription (c. 798) indicates that a Chinese-influenced Buddhist sect was widely practiced among the Red River dwellers during the Tang period. Buddhist scriptures claim that in 580, an Indian monk named Vinītaruci arrived northern Vietnam and founded the Thiền patriarch (Vietnamese Zen Buddhism). In 820, a Chinese monk named