Star Swirl the Bearded

Star Swirl the Bearded is a well-known pioneer of magic, appearing in the show as Twilight Sparkle's costume in Luna Eclipsed and mentioned at other times. There is a wing in the Canterlot Library named after him that houses time-related spells.

Development
M.A. Larson, the writer of Luna Eclipsed and It's About Time, selected the name Star Swirl out of a list of pre-approved locations and names by Hasbro, then added "the Bearded" because it didn't sound "quite old enough". Larson stated that Twilight Sparkle "would be the kind who'd idolize the great minds of the past." The name Star Swirl was given by Hasbro to several Earth pony mares in previous My Little Pony toy lines, and has been used in the current toy line for another Earth pony mare. Online promotional materials posted by The Hub's Facebook page and Wired's Underwire blog have both spelled it "Star Swirl" as the current toy line has, though Meghan McCarthy and Larson (both on Twitter) and The Hub's Facebook app Ponyscopes have spelled it "Starswirl".

Depiction in the series
Star Swirl the Bearded is first mentioned by Twilight in Luna Eclipsed when she explains her costume to Spike. She calls Star Swirl "the father of the amniomorphic spell", "the most important conjurer of the pre-classical era", and adds "he created more than 200 spells! He even has a shelf in the Canterlot library of magic named after him." Later in the episode, Princess Luna recognizes Twilight's costume as Star Swirl and compliments her for it, stating she "even got the bells right," but other ponies that Twilight asks about her costume guess that she's a "weird clown" or a "country music singer". In Dragon Quest, a photo shows Twilight wearing the costume.

According to the pageant staged in Hearth's Warming Eve, Star Swirl was the mentor of Clover the Clever, one of the founders of Equestria. In It's About Time, Twilight searches for time spells in a wing of the Canterlot library that is named after Star Swirl. Twilight says it's "the most secure section of the archives", and needs to be let into the section by one of the guards patrolling the library.

Merchandise
Hasbro uses the name Star Swirl for an Earth pony mare with a powder-blue coat and a light purple and pink mane. Both toys of Star Swirl have only been released outside of the United States: the Playful Ponies version packaged with Rarity in the special edition of the Royal Gem Carriage vehicle set, and the mini-figure version as part of the second wave of mystery packs. According to the collector card included with the mystery pack toy, Star Swirl "always sparkles!"

WeLoveFine sells an art print with a fan-design of Star Swirl the Bearded and a T-shirt showing Twilight Sparkle dressed up as Star Swirl the Bearded.

Promotional material
In The Hub's Facebook app Ponyscopes, of the horoscopes for January 8th, 2013, attributed to Twilight Sparkle, the Sagittarius horoscope is "It's time to restock supplies! I always carry extra quills, scrolls, ink, books, and Starswirl the Bearded's tenants at all times."