Jiang Ziya, is he a historical figure?

Feb 2019
Read about him on wiki and he seems to have been an outstanding individual. How much of his life and of the king he served(King Wen of Zhou) has any historical basis?

"Today, Jiang Ziya is regarded as one of the greatest strategists in both Chinese history and the world, and is honored as the first famous general and progenitor of strategic studies."