Who is the princess of the sun in the My Little Pony universe?

The princess of the sun in the My Little Pony universe is Princess Celestia.

Princess Celestia is an alicorn—a pony with a horn and wings—and the longtime ruler of Equestria in My Little Pony: Friendship Is Magic. Her signature responsibility is raising the sun, while her younger sister, Princess Luna, governs the night and moon. Celestia’s white coat, multicolored flowing mane, tall stature, and sun cutie mark reinforce her connection with daylight.

Celestia is also Twilight Sparkle’s mentor. At the beginning of the series, she sends Twilight to Ponyville to learn about friendship, setting the central story in motion. The show’s history says Celestia ruled alongside Luna until Luna became Nightmare Moon; Celestia then banished her sister to the moon for 1,000 years before the Mane Six helped restore her.

Princess Luna is therefore the most likely confusion: she is associated with the night, not the sun. Princess Cadance rules the Crystal Empire, while Princess Twilight eventually succeeds Celestia as Equestria’s ruler.