Pendant of Virtue

The Pendants of Virtue appear in A Link to the Past and are required in order to retrieve the Master Sword. Link must travel to three dungeons and collect each one before going to the Lost Woods to find the Master Sword. An ancient Hylian verse on the pedestal of the Master Sword about the pendants reads:

"The Hero's triumph on Cataclysm's Eve Wins three symbols of virtue. The Master Sword he will then retrieve, Keeping the Knights' line true."

The Pendant of Courage

 * Location: The Eastern Palace
 * Guardian: Armos Knights

The Pendant of Wisdom

 * Location: The Desert Palace
 * Guardian: Lanmolas

The Pendant of Power

 * Location: The Tower of Hera
 * Guardian: Moldorm

Trivia

 * While not entirely certain, there is a strong possibility that the Pendants could have some connection to or be the actual remains of the Spiritual Stones of The Legend of Zelda: Ocarina of Time. Both the Pendants and the Spiritual Stones were needed to clear Link's way to wielding the Master Sword and both the three Pendants and the three Spiritual Stones were green, red and blue.  It is highly possible the Spiritual Stones were made into three Pendants of Virtue over the course of the many centuries that pass between The Legend of Zelda: Ocarina of Time and The Legend of Zelda: A Link to the Past.