He enslaved them.
There was only 1 Pharaoh that enslaved the Hebrews, but his name is not mentioned in the Torah.
To keep him from death. the pharaoh though there were too many Hebrews and decided to kill the new born male babies.
They were slaves to Pharaoh.
Because the Hebrews were starting to outnumber the Egyptians in population.
God brought many plagues upon Pharaoh's country (Exodus ch.7-12).
After the Pharaoh died, and the new Pharaoh took over, they were enslaved.
Matzoh
The Torah doesn't mention the name of the Pharaoh who enslaved the Hebrews.
makot(plaques)
Pharaoh, the one who wouldn't let the Hebrews go.
Passover celebrates the time when the Hebrews fled from Egypt and Moses led them, chasing after them was Pharaoh's army. Moses then parted the sea to let the Hebrews cross and closed the sea on Pharaoh's army. I xxx
Hebrews were never slaves in Egypt. There is no record of such thing beyond a book of bias written by the Jews.