Exodus 12:29

And it came to pass at midnight that the Lord smote all the first-born in the land of Egypt, from the first-born of Pharao that sat on the throne, to the first-born of the captive-maid in the dungeon, and the first-born of all cattle.

And it came to pass, that at midnight the Lord smote all the firstborn in the land of Egypt, from the firstborn of Pharaoh that sat on his throne unto the firstborn of the captive that was in the dungeon; and all the firstborn of cattle.

At midnight, Yahweh struck all the firstborn in the land of Egypt, from the firstborn of Pharaoh who sat on his throne to the firstborn of the captive who was in the dungeon, and all the firstborn of livestock.