From en.wikipedia.org

Rhodopis, a Greek slave, works in the household of her Egyptian master. Though kind, he spends most of his time sleeping, and is therefore unaware of her harsh treatment at the hands of his other servant girls. Because Rhodopis is both fair-complexioned and a foreign slave, the other servants tease her and order her around.

After her master sees Rhodopis dancing skillfully by herself, he gives her a pair of rose-gilded slippers. The other servants resent this treatment and use Rhodopis more harshly than before.

One day, Pharaoh Ahmose I invites the people of Egypt to a celebration in Memphis. The other servants prevent Rhodopis from attending with them by giving her a long list of chores to complete.

While she is down by the river washing clothes, her slippers become wet and she places them in the sun to dry. Suddenly, the falcon Horus swoops down, snatches one of the slippers, and flies away with it. Rhodopis stores the other slipper in her clothing.

During the celebration in Memphis, the falcon drops the slipper in the Pharaoh’s lap. Realizing that it is a sign from Horus, he decrees that all the maidens of the kingdom must try on the slipper, and that he will marry the one whose foot it fits.

The Pharaoh’s search for the owner of the slipper eventually leads him to Rhodopis’ home. Though Rhodopis hides when she sees the Pharaoh’s barge, he sees her and asks her to try the slipper. After demonstrating that it fits her, she pulls out its mate, and the Pharaoh declares that he will marry her.