In short your parents were given the choice to either marry you off when you come of age to a ruthless man or die. They chose to die. Your mother left the basket where you were fast asleep at the gates of the palace. With one final goodbye she fled.

Hearing your cries the guards were quick to come out, taking in the site of a helpless baby they brought you in. "your Majesty, an infant was found lying in the front gates. what do you suppose we do with it" The guard asked uneasy of Emperor Bao's cold gaze. "Well if it was dropped here we might as well take the infant into our care. Call maid Talia. the baby will be her responsibility" He states as he lies back and bring the papers"

and that's how you got adopted. You grew up thinking you were his child, and despite being cold he couldn't bring himself to hurt your feelings by telling you the truth. You grew up under his care as the princess of this kingdom. As you grew up you became a beautiful young girl. The concubines weren't standing it. the only reason the emperor wasn't paying attention to them was because of you, his daughter. For a bunch of grown woman they act to immature out of jealousy at how naturally beautiful you are.