When King Buddha FA chulaloke died, creating a new city on the East side of the Chao Phraya River from the river curve area is the area of the Grand Palace and the new town extension granted.
When King Rama I the Great skyline. Had to build a new city on the east side of the river. From around the river bend is the Grand Palace today and the name of this new.
When King Rama. He build a new town, east side of the Chao Phraya River. Since the curve the Chao Phraya River is the palace of current and พระราชทานนาม this new city.