1920 - Vietnamese communist organizer Ho Chi Minh begins propaganda work among the Vietnamese expatriates in northeastern Siam.
1923, Dec 17 - Siam adopts the metric system of weights and measures.
1925 - Rama V dies at the age of 44. Having remained a bachelor until the age of 38, his only son is born a day before his death. After the death of King Rama VI, his younger brother Prince Prajadhipok (Nov 8, 1893 - May 30, 1941) succeeds the throne under the title Rama VII. As he is the 76th child of King Chulalongkorn and only the fifth son of the one of Chulalongkorn’s wife the King had elected Queen, he was only fourth in line of succession after King Rama VI. As he ascends the Siamese throne only because his elder brothers had, unexpectedly, all died early, he was not well prepared for the task, from his up-bringing as well as personally. Furthermore, he was not in the best of health (and only reaches the age of 48).
1927, Nov 30 - The Privy Council meets for the first time after its creation in 1877 and elects Prince Bidyalangkorn as its President.
1931 - The Siam division of the Communist Party of China is organized. It is dedicated to furthering the ambitions of the Chinese communists rather than to a Thai revolution.
1932, Jun 24 - The secret People’s Party, composed of Siamese educated in Europe, some of them in high positions in the royal government or the military, topples the absolute monarchy while King Prajadhipok is at his summer residence in Hua Hin. Some 40 princes, high government officials and senior military officers are arrested and held hostage at the Ananlasanakan Hall in Bangkok. The group send the following telegram to King Prajadhipok:
"The People’s Party consisting of civil and military officials have now taken over the administration of the country and have taken members of the Royal Family such as H.R.H. Prince Nakhon Sawan as hostages. If members of the People’s Party have received any injuries, the Princes held in pawn will suffer in consequence. The People’s Party have no desire to make a seizure of the Royal possessions in any way. Their principal aim is to have a constitutional monarchy. We therefore invite Your Majesty to return to the Capital to reign again as king under the constitutional monarchy as established by the People’s Party. If your Majesty refuses to accept the offer or refrains from replying within one hour after the receipt of this message, the People’s Party will proclaim the constitutional monarchical government by appointing another Prince whom they consider to be efficient to act as King."
King Prajadhipok replied with the following telegram:
"I have received the letter in which you invite me to return to Bangkok as a constitutional monarch. For the sake of peace; and in order to save useless bloodshed; to avoid confusion and loss to the country; and, more, because I have already considered making this change myself, I am willing to cooperate in the establishment of a constitution under which I am willing to serve. Furthermore, there is a possibility that, if I decline to continue in my office as king, the foreign powers will not recognize the new government. This might entail considerable difficulty for the government. Physically I am not strong. I have no children to succeed me. My life expectancy is not long, at least if I continue in this office. I have no desire for position or for personal aggrandizement. My ability to advance the progress of the race alone constrains me. Accept this sincere expression of my feelings."
