Sir Arthur Ignatius Conan Doyle (22 May 1859 – 7 July 1930) was a Scottish writer and physician, most noted for creating the fictional detective Sherlock Holmes and writing stories about him which are generally considered milestones in the field of crime fiction. He is also known for writing the fictional adventures of a second character he invented, Professor Challenger, and for popularising the mystery of the Mary Celeste. He was a prolific writer whose other works include fantasy and science fiction stories, plays, romances, poetry, non-fiction and historical novels. Doyle is often referred to as "Sir Arthur Conan Doyle" or simply "Conan Doyle" (implying that Conan is part of a compound surname, as opposed to his given middle name). His baptism entry in the register of St Mary's Cathedral, Edinburgh gives "Arthur Ignatius Conan" as his given names, and "Doyle" as his surname. It also names Michael Conan as his godfather. The cataloguers of the British Library and the Library of Congress treat "Doyle" alone as his surname. Steven Doyle, editor of the Baker Street Journal, has written: "Conan was Arthur's middle name. Shortly after he graduated from high school he began using Conan as a sort of surname. But technically his last name is simply 'Doyle'." When knighted, he was gazetted as Doyle, not under the compound Conan Doyle. Nevertheless, the actual use of a compound surname is demonstrated by the fact that Doyle's second wife was known as "Jean Conan Doyle" rather than "Jean Doyle".