The original Royal Clock Tower, known as Phra Thinang Phuwadon Thasana, was built between 1852 and 1857 inside the Grand Palace during the reign of King Mongkut (Rama IV). It was part of a European style building complex called Phra Apinao Niwet, designed and supervised by Prince Chumsai, Krom Khun Ratchasiwikrom, then Director of the Royal Crafts Department. This complex was one of the earliest examples of Western architecture in Siam. It housed a reception hall for foreign dignitaries, spaces for displaying royal gifts, a library, and a high tower fitted with a four sided clock to keep time visible from the river.

Before the tower, time in Bangkok was marked by the sound of drums (at night) and gongs (during the day), a method known as “thum–mong”. However, this system was imprecise and was seen by Western visitors as old fashioned. King Mongkut ordered the clock tower to modernise timekeeping in the capital, creating a landmark that rivalled religious buildings in height and symbolising Siam’s progress. It introduced a standard time system, often referred to as “Bangkok Mean Time”, to help unify the city’s sense of time.

The Royal Clock Tower also led to the establishment of the country’s first official department responsible for clocks. Specialists were trained abroad to maintain the mechanism, which combined astronomy and mechanical science from the West with traditional Thai astrology. The department, overseen by Prince Alangkarn Kitpricha, ensured accurate timekeeping for Bangkok.

The original clock tower was eventually demolished during the reign of King Chulalongkorn (King Rama V) due to structural problems. Although its design was not entirely accurate from a Western architectural perspective, the tower served as a strong symbol of modernity and the ambition to present Siam as a civilised nation in the 19th century.

In 1982, to celebrate 200 years of Rattanakosin, a replica of the Royal Clock Tower was constructed on Maha Chai Road, opposite Wat Pho. This new tower recalls the original structure and stands as a memorial to Siam’s early efforts at adopting Western science and architecture while maintaining Thai cultural identity.