Where did the phrase “to carry the torch for one” come from and What does it mean?

It is the torch of love that is understood in this modern American term, though sometimes no more than the torch of loyalty, for the “torchbearer” is one who is loud in his praise of a friend.

But the torch has long been an emblem of enlightenment and of burning devotion, and, in 1775, Richard Sheridan used the expression, “The torch of love,” in his epilog to The Rivals.