Frederick Treves was born on February 15 1853. He was a surgeon at London Hospital and in the show is working with Joseph Merrick (The Elephant Man). He first appears in season two, helping perform surgery on Sgt. Morrison of K Division. He cares for Merrick until Merrick dies by the hand of Jedediah Shine. Treves is always suspicious of Reid and his scheming with Linklater and Merrick but is not seen again in the show until seven years later when Reid returns to the hospital. In season four Treves is first seen giving a lecture on Joseph Merrick. Reid speaks to him as to why a man would bleed someone and collect their blood and Treves responds "Knowledge," "Blood is life," he is not seen in the show after that.
Historically Sir Frederick Treves was a surgeon at London Hospital who brought Joseph Merrick in after he saw him at a freak show. He performed the first appendectomy in 1888. he then became a field surgeon in the Second Boer War in 1899 and published an account of his experiences. He served the Royal Family until 1910. Treves died on December 7 1923.