A beast mentioned in the Book of Job, translated to unicorn in the King James version of the Bible. Also speculated to refer to the Arabian Oryx.

"Will the unicorn be willing to serve thee, or abide by thy crib? Canst thou bind the unicorn with band in the furrow? or will he harrow the valleys after thee? Wilt thou trust him, because his strength is great? or wilt thou leave thy labour to him? Wilt thou believe him, that he will bring home thy seed, and gather it into thy barn?" (Book of Job 39:9–12 trans. KJV)}

The Book of Job is thought by many to be the oldest book in the Bible

Legendary creatures