Long ago, the King and Queen of a little-known kingdom of marginal fame were blessed with septuplets.  Though it took the Queen’s life, the seven were born into this world together, survived together, and eventually thrived together.  However, having seven capable sons became a thorny problem for the aging King as the princes came of age.  

The law was very clear: only the first-born son was entitled to become King.  That had been the tradition since time immemorial, and the people would accept no other arrangement.  With the seven being cut from their mother’s womb, however, there was no clear contender.

On the eve of their 25th birthday, when the King was expected to hand over his crown, the seven gathered expectantly to hear the decision.  Looking into the eyes of each son, and before the assembled witnesses, the King stated simply: “I leave my kingdom in the hands of all seven of you.  You have grown strong together and now you shall rule together.  All hail the Seven Kings!”  And with that he produced a chest filled with seven wondrous items, crafted in secret over many long years.  Each prince received one as a gift, according to his natural abilities, and swore to serve the kingdom and support his brothers for the rest of his life.   

The magic items were created for several important reasons:
To suit the nature of each prince and allow him to fulfill his individual destiny.
To pacify the princes with enough power/adventure that they would not be tempted to tear the kingdom apart.
To symbolize their interdependence on each other.
To encourage cooperation and brotherhood among the brood.