Pharaoh actually hardened pharaohs own heart
Oh? Your Book disagrees.
9 And the LORD said unto Moses, Pharaoh shall not hearken unto you; that my wonders may be multiplied in the land of Egypt.
10 And Moses and Aaron did all these wonders before Pharaoh: and the LORD hardened Pharaoh's heart, so that he would not let the children of Israel go out of his land.
"The wretched world lies now under the tyranny of foolishness; things are believed by Christians of such absurdity as no one ever could aforetime induce the heathen to believe." - Agobard of Lyons,
ca. 830 AD