Merlin

Merlin was a legendary figure in the Terran stories of King Arthur of Ancient Britain. Merlin was commonly depicted as a wizard or magician who had a preternatural knowledge of the future, and served as adviser to the king. Some versions of the legend claim he was immortal, or that he lived his life backwards through linear time.

Parneb of Thebes claimed to have known Merlin in the 12th century BCE, though by the name "Ahkarin". 

In 2269, Captain James T. Kirk encountered an immortal human named Flint, who revealed that he had been Merlin, as well as a warrior named Akharin.