Ok; did it predate the institution of PASSOVER?
It was pagan. Ishtar and Tamuz and Nimrod. It was a pagan legend that involved death and ‘resurrection’ held in the spring time. And is your question did it happen before God had the first passover? The stories and history says yes it was before the time of the pharaoh’s. Passover is not Easter and Easter is not Passover. Do not confuse the two. But the question is truly beside the point.