James Tilly Matthews (1770 – 10 January 1815) was a British merchant of Welsh and Huguenot descent who was committed to the Bethlem Royal Hospital in 1797 after developing politically charged delusions which led him to disrupt sessions of the House of Commons of Great Britain. These delusions were documented in an 1810 book titled Illustrations of Madness, including Matthews' belief that a group of spies were using an "air loom" to secretly torment him from a distance. Modern historians consider Matthews to be the first fully documented case of schizophrenia.