Portuguese diplomat Fernão Pires de Andrade arrived at the mouth of the Pearl River in June 1517 and asked the naval commander of Nantou for permission to take his ships to Guangzhou.

When official reception from Guangzhou arrived, tensions relaxed, and the Portuguese were received with much pomp as well as the right to trade their goods for silk and porcelain.

Upon arriving with three ships, Simão executed a Portuguese citizen and built a fort on Tunmen, barring other foreigners from conducting trade.

[2][4] Simão's pirating activities greatly angered both the Chinese people and the court, which led Ming officials to order the eviction of the Tunmen Portuguese.

The newly appointed Grand Secretary, Yang Tinghe, announced the rejection of the Portuguese embassy the day following the emperor's death.

In response, commander Wang Hong assembled a squadron of fifty ships and imposed a blockade on the Portuguese as well as the Siamese and Patani junks they had requisitioned.

A strong wind arose at this point and scattered the pursuing Ming fleet, which allowed the Portuguese to retreat and make their way to Malacca in October.

Simão de Andrade's activities also continued for decades after he left Guangzhou in 1520, and he sailed to Xiamen and Ningbo where he established settlements.

[12][13] The new Portuguese trading presence in Guangdong got off to a solid start in 1554 when the merchants Leonel de Sousa and Simão d'Almeida offered bribes to Wang Bo, the vice-commissioner for maritime defense.

The most important incident of bribery occurred in 1582 when the viceroy of Guangdong and Guangxi summoned Macau's chief officials for a meeting.

Remembering the fate of Tomé Pires decades earlier, Macau's leaders chose an elderly judge and Italian Jesuit to go in their place.

This leads some researchers to link the Tunmen of Ming times to Tuen Mun in the New Territories of Hong Kong.