Wikipedia
Isariyabhorn
His Royal Highness Prince Isariyabhorn or Phra Chao Boromwongse Ther Phra Ong Chao Isariyabhorn ( RTGS: Isariyaphorn) (21 October 1888 – 21 September 1892), was the Prince of Siam (later Thailand. He was a member of Siamese Royal Family. He is a son of Chulalongkorn, King Rama V of Siam.
His mother was The Noble Consort (Chao Chom Manda) Mom Rajawongse Kesara Sanidvongse, daughter of Mom Chao Savasdi Sanidvongse. He had a younger brother, Prince Anusara Siriprasadh
Prince Isariyabhorn died in babyhood on 21 September 1892, at the age of only 3 years 11 months.