This interesting and seldom encountered issue should be considered the first Crown size coin of Thailand. Several Royal proclamations were issued specifically pertaining to the use and exchange of foreign silver "Flat coins" that were imported for trade. Initially, the exchange rate fluctuated as the supply of imported specie could not keep up with the demand of re-minting them into Pot Duang (Bullet coinage). The 7 January 1857 decree finally stipulates that a fixed rate of exchange was one Tamlung one Baht (five Baht) to three foreign silver coins and that they could be exchanged at the Royal Treasury. Since different types of foreign coins were being imported many merchants were hesitant to accept them in trade at the prescribed rate. Later several more decrees were issued to try to address the hesitation of the merchants refusing to accept them in transactions even going so far as penalizing those who declined them. Eventually, the most common coin in circulation at the time, the Mexican "Dollar", often referred to as "Bird" coins became the standard being marked on the obverse with the Chakra wheel and Mongkut emblems.
Purportedly from the Charles Stuart Collection.
Estimate: $7000 - $10000