1/2 Tamlueng - Rama IV

Rama IV — better known in the West as King Mongkut — came to the throne in 1851 after spending 27 years as a Buddhist monk, during which time he taught himself Latin and studied Western astronomy with enough precision to accurately predict the solar eclipse of August 1868. His reign marked a deliberate turn toward Western monetary conventions, and gold coinage of this period reflects the transitional moment before Thailand's eventual adoption of decimalized currency under Rama V.

The half tamlung sits within a weight system derived from ancient Southeast Asian trade standards, with the tamlung itself equivalent to four baht — a unit still in use today, long after the coins themselves vanished from circulation.