Phra Sumen Fort built in 1783 Bangkok Thailand

Phra Sumen & Mahakan Fort Forts built to protect the city
Today only two forts remain out of 14 that were built more than two centuries ago. Phra Sumen Fort is one of the remaining forts that was built during the end of the 18th century to protect Bangkok from possible invasions.
New capital
When King Buddha Yodfa Chulaloke (Rama I) ascended the throne as the first ruler of the Chakri dynasty in 1782, he decided to establish Bangkok as the new capital of the Kingdom. The capital was founded on the Eastern side of the Chao Phraya river in the Rattanakosin area.

Fortifications
Because only a few years before that, in 1767, the Burmese had completely destroyed the old capital of Ayutthaya, the King had a number of fortifications built and canals dug out to protect Bangkok. Phra Sumen Fort was built in 1782 as one of 14 forts of which only two remain today, the other one being Mahakan fort.