“The construction of Phya Thai Palace began in 1909. It was built at Rama V’s behest so that he might stay there and look out over the farms, plantations and livestock in the area. The palace grounds included those areas directly opposite the palace. He also had a complex included in the compound where the Royal Ploughing Ceremony might take place, since used on many occasions.

During the reign of King Rama VI, Queen Saovabha, then Queen Mother, was invited to live there, which she did until her death in 1920. Rama VI then had the entire palace grounds demolished, leaving only the Devaraja Sabharamaya Hall (พระที่นั่งเทวราชสภารมย์ Phra Thi Nang Thewarat Sapharom) and Throne Hall, and ordered that the many new palace halls be built together to form a new Royal Phya Thai Palace. King Rama VI then lived at the palace until the later years of his reign.”[1]

[1]-https://en.wikipedia.org/wiki/Phaya_Thai_Palace