What did one buy a King, even a boy-King, who planned to sail to the end of his own world?

He talked of it in such a way that she could almost feel how long time that might be, in days and weeks. She had not seen it, but enough tales of their own sea going on and on until it's end.

"Has anyone gone over the edge and returned?" It a was a doubtful, but worthy question, after all. They believed there was an edge but no one had returned in their's.