Wat Arun is one of the few surviving legacies from the Chakri dynasty of Thailand. The term Wat refers to a group of religious buildings generally enclosed by a wall with several gateways. During the golden era of Ayutthaya, ships of various nations sailing up and down the 'River of Kings' would make a stop at the junction of the Chao Phraya River known as Thonburi, to replenish supplies and provisions which were available abundantly in this area. The sailors would stop in obeisance in front of the old temple formerly known as Wat Makok or Wat Makok Nok.
It is said that the royal fleet of King Taksin, the founder of the former capital of Thonburi, arrived at Wat Makok Nok precisely at dawn. He stopped his vessel and disembarked to pay homage to the Holy Relic inside the pagoda, and the temple was subsequently referred to as Wat Chaeng - the Temple of Dawn. When King Taksin crowned himself the monarch, the temple was designated a royal temple within the grand palace, as it was the first place in Thonburi to catch the morning light. Unfortunately, King Taksin treated the temple monks badly, expelling them so that he could worship privately in the temple. The Wat housed the statue of the Emerald Buddha, before it was moved to Wat Phra Kaeo in 1785.