"...In a dark tree there hides
A bough, all golden, leaf and pliant stem,
Sacred to Proserpine. This all the grove
Protects, and shadows cover it with darkness.
Until this bough, this bloom of light, is found,
No one receives his passport to the darkness
Whose queen requires this tribute. In succession,
After the bough is plucked, another grows,
Gold-green with the same metal. Raise the eyes,
Look up, reach up the hand, and it will follow
With ease, if fate is calling; otherwise,
No power, no steel, can loose it."

-Virgil's Aeneid, Book Sixth
Rolfe Humphries, trans.