About Prince John of the United Kingdom
Prince John of the United Kingdom (John Charles Francis; 12 July 1905 – 18 January 1919) was the fifth son and youngest of the six children of King George V and Queen Mary. At the time of his birth, his father was heir apparent to John's grandfather Edward VII. In 1910, John's father acceded to the throne upon Edward VII's death, and John became fifth in the line of succession to the British throne. In 1909, it was discovered that John had epilepsy. In 1916, as his condition deteriorated, he was sent to live at Sandringham House and kept away from the public eye. There, he was cared for by his governess, Charlotte "Lala" Bill, and befriended local children whom his mother had gathered to be his playmates. He died at Sandringham in 1919 after a severe seizure, and was buried at nearby St Mary Magdalene Church. His illness was disclosed to the wider public only after his death. John's seclusion was subsequently brought forward as evidence of the royal family's inhumanity. However, contrary to the belief that he was hidden from an early age, John was a fully-fledged member of the family for most of his life, appearing frequently in public until after his 11th birthday, when his condition became severe.
Biography source: Wikipedia. The profile adds birthday-specific historical context from the Celebs Birthday Today editorial database.