The document traces the history and development of stringed instruments from the 9th century rebab to modern Stradivarius violins. It discusses how instruments evolved to include more strings and different shapes and woods over time. The document focuses on luthier Antonio Stradivari and his innovations in violin making during the late 1600s. It also notes that while his varnishes were once thought special, they are now known to be similar to modern varnishes. Stradivarius violins remain highly valued, with the most expensive selling for over $15 million.