Treaty of Amity and Commerce

The Roberts Expedition -
Edmund Roberts (1784-1836), an agent of the United States, was tasked with visiting the major empires and kingdoms of Asia to seek trade agreements on behalf of the United States, the first diplomatic mission of its kind for the young nation. Roberts and the crew of the USS Peacock arrived in the Gulf of Siam in February 1833, nearly one year after departing from Boston, Massachusetts.

Bangkok had been the Siamese capital for only half a century when the Roberts expedition arrived, yet it had quickly developed into a bustling hub for trade.

During their stay, Roberts met primarily with Dit Bunnag, who was at this point the phrakhlang (minister of foreign affairs and finance) and thus responsible for the negotiation of treaties.

Three years after it was initially drafted, the Treaty of Amity and Commerce, the first agreement of its kind between the United States and an Asian nation, was fully ratified by King Nangklao, the U.S. Congress, and President Martin Van Buren (1782-1862).

Since the two countries did not adequately understand each other’s language at the time, the document was also transcribed in Portuguese and Chinese “to serve as testimony to the contents of the Treaty.”

The primary objective of this agreement was to establish a system of duties to regulate the import and export of goods by American merchants, thereby promoting trade. The treaty’s success was limited by the geographical distance that separated both nations, but still represented an important step for the United States and Siam in their development as world powers.