Alexander the Great Sacrificed at the Jerusalem Temple
Many gentiles incorporate the God of the Jews into their pantheon. In the Hellenistic and early Roman periods numerous dignitaries offered sacrifices or gifts tot he God of the Jews at his temple in Jerusalem. Even Alexander the Great was said to have done so.
If the dignitary was the ruler of the Jews, the political meaning of his gesture was clear; by sacrificing to the God of the Jews, he confirmed his sovereignty over the Jews because he represented the people before their God. The theological meaning of the gesture was clear as well. The Jews are a respectable nation, and their God is a respectable deity. An empire has many nations and many gods.
More striking, perhaps, is the conduct of private gentiles, people who were not generals or monarchs or officials, who worshiped in the Jerusalem temple or sent money to support it. Josephus mentions gentiles from across the Euphrates who came to the temple to bring a sacrifice, and God-venerating gentiles from Asia and Europe who enriched the temple with their donations. The Gospel of John mentions Greeks who went up to to worship at the temple at the Passover.
From The Beginnings of Jewishness: Boundaries, Varieties, Uncertainties by Shaye J.D. Cohen