¥The originals were probably written over the period 1400-400 BC.
¥The earliest fragments discovered to date are among the Dead Sea Scrolls:
parts of Exodus and Samuel from ~250 BC.
¥The earliest complete book (Isaiah) comes from the same find, dating to
~125 BC.
¥The earliest complete copy of the whole OT, surprisingly, is a Greek
translation, from ~AD 350.
¥The earliest complete Hebrew manuscript only goes back to about AD 950.