Talk:Shadow Play - Part 1/@comment-10390252-20170923174736/@comment-4087607-20171009005538

The Six Pillars represent the six elements that are similar to the Elements of Harmony that the Mane Six represent as well.
 * Star Swirl/Twilight - Sorcery/Magic
 * Rockhoof/Applejack - Strength/Honesty
 * Flash Magnus - Bravery/Loyalty
 * Mistmane/Rarity - Beauty/Generosity
 * Meadowbrook/Fluttershy - Healing/Kindness
 * Somnabula/Pinkie Pie - Hope/Laughter

So the Six Pillars were the original Mane Six. Even though Star Swirl never understood friendship in his time.