About Prince Erik, Duke of Västmanland
Prince Erik, Duke of Västmanland (Erik Gustav Ludvig Albert; 20 April 1889 – 20 September 1918) was a Swedish and Norwegian prince. He was the third and youngest son of King Gustav V of Sweden and Victoria of Baden and was known to be disabled. == Life == Prince Erik had epilepsy and mild intellectual disability. His exact condition has not been published, but he may have had an injury at birth or been affected by his mother's strong pre-natal medication for pneumonia. He had pangs of severe anxiety, and Victoria called him "my much loved child of grief". He was described as handsome and physically healthy. His mental disability was not noticeable in brief conversation, but would become apparent if he was engaged at length. Because of his condition, he was seldom seen in public and led a quiet life away from the public eye, similar to the life of Prince John of the United Kingdom. Because he was a member of the royal family, he was present in official royal photographs, but he had no official tasks. During 1907 to 1909, a residence was built for him away from the public eye in Djursholm, a relatively new garden community north of Stockholm.
Biography source: Wikipedia. The profile adds birthday-specific historical context from the Celebs Birthday Today editorial database.