Somdet Phra Srinagarindra Boromarajajonani (Sangwan; 1900–95)

In the history of Thailand or old Siam, no mother of any king played a more important role in national affairs than Somdet Phra Srinagarindra Boromarajajonani. She was the mother of two monarchs, King Ananda (1925–46) and King Bhumibol (1927–2016). A self-reliant, highly independent woman, she is among the most flamboyant characters of twentieth-century Thailand. Her strong willpower and resolve arguably played a role in a historic battle against the spectre of Communism in the Kingdom.

Best known as Somdet Ya, the Royal Grandmother, or Princess Mother, her original name as a commoner was Sangwan. By the middle of the 1960s, at the height of the Cold War in Asia, the Princess Mother had become a leading national figure.

In 1964, she returned from Switzerland to live permanently in Thailand. She was sixty-four years old, and her nation had become a staunch ally of the United States of America. In that same year, Prime Minister Field Marshal Thanom Kittikachorn strongly supported the US Congressional resolution on the Gulf of Tonkin incident.

The Gulf of Tonkin incident was an international confrontation that led to the United States engaging more directly in the Vietnam War. It involved a confrontation on 2 August 1964 and a claimed or presumed confrontation two days later between ships of North Vietnam and the United States in the waters of the Gulf of Tonkin. In this incident which occurred in a medium-sized gulf at the northwestern portion of the South China Sea, located off the coasts of Tonkin (northern Vietnam) and South China, the original American report blamed North Vietnam for both incidents.

Although later informed reports discounted the veracity of the second incident, it was used at the time by the US State Department and other government personnel to justify an escalation by the United States to a state of war against North Vietnam.

On Sunday, 2 August 1964, the destroyer USS Maddox claimed to have been attacked by North Vietnamese Navy torpedo boats.