Here is a revised outline of the Cup of Kings I think I have managed to get everyone's suggestions integrated into it.
*EDIT* Changed the consequence of not following the god's orders,
(Ascension)If we stay with the cup I think that he just needs to drink from it once a day/week/month so that he doesn't have to hang it around his neck or keep it in a lockbox. It should be sort of ordinary looking so as to not look really valuable which would increase it's likelihood of being stolen. If it's got gems dripping all over it then someone's gonna want to steal it about every 30 seconds of the day. If it looks rather plain then no one would even suspect. This also makes finding it a bit more complex as well.
(Neonknight)I Like the cup idea most. Is a great visual reference, and allows for very spectacular/impressive imagery of coronations where the King takes his first 'sip' during the ceremonies when he is anointed etc. For a little more fun, think of Indiana Jones 3; Quest for the Holy Grail. The cup was an unimpressive cup. Perhaps this cup of kings is very similar
(Korash)also love the idea of the Cup being used in the coronation to legitimize the new King (or Queen), and if the King is a "Chosen of the Gods to Rule" that would explain the need for regular use of the Cup in say a monthly Replenishing of the Covenent. I also like the idea that it would added too by subsequent holders, but if it gets oo big it would make it real hard to steal. Anothere thought is that "Cup" can be what it was initially, but with the additions could have changed to something altogether different. Thinking a smallish cup or wine glass sort of thing, and ppl adding to the stem to the point where the Cup is now more of a rod with the Cup at the top.
(jfrazierjr)Kingdom was found at place X.
Original use of cup tied to place X.
Capital moved to Place Y due to _______(ummm I don't know.. I can't be too serious unless you have a period where the was no king due to not being able to reach place X).
Each year on the summer solstice(fit some specific date in here), the king must drink from the cup while at place X or lose his right to be king.
The Cup of Kings
The Cup of Kings is an ancient magical device given to the first king of this land by a avatar of a benevolent god who wished for the strife among her people to end. She chose a "true" leader that would unite the fractured land into one strong kingdom.
The first king to hold the cup(insert name) was told by the avatar of (insert name) that he must drink from the cup on the night of the summer solstice yearly at the exact place that the cup was given to him. Failure to do this would result in the king falling from the god's favor, A terrible prospect that would lead to the king falling gravely ill and the kingdom to crumble. He was to make this offering to the god for all the years of his life. All his descendants were also bound by this promise.
In the beginning, the cup was a simple chalice of dull silver with a ring of gold knot work around it's rim. Over time the cup changed to what it is today a elongated rod of silver with the cup at it's top. It is approximately 3 feet in length. Although the true reason for the cup's transformation is unknown, sages surmise that as the kingdom grew in strength and prosperity the cup changed to reflect the gods pleasure.
The cup is only filled with liquid once a year. No one is sure what the liquid is although it is a safe assumption that it is a intensely magical substance. Kings have said that it tastes like the finest wine they have ever had.
The original location of the meeting between the first king and the avatar was a clearing in a forest in the center of the kingdom. This is where the first capital of the kingdom arose. Several hundred years ago an evil rival of the king poisoned the water of the capital forcing the city's relocation to it's present location. Every summer solstice the king travels to this spot to make his offering to the god and drink from the cup.
The Cup serves as a manifestation of the benevolent god in the kingdom. She provides the magic that allows kings to be kings. the magic provides protection from various things including mind control and possession. Each King is crowned in the forest clearing on the summer solstice so that they may drink from the cup and receive the gods blessing.