Compare and contrast Keats' "La Belle Dame sans Merci" with Tennyson's "The Lady of Shalott"?

These two poems Keats' "La Belle Dame sans Merci" and
Tennyson's "The Lady of Shalott" are expressions of unrequited love, the contrasts
between the world of reality and the world of imagination, and the difficulty of the two
worlds coexisting.

Both poems are about unrequited love.
Keats' poem concerns a pale knight who after experiencing a tryst with a beautiful
"fairy's child" feels abandoned and dejected on a "cold hillside."  In Tennyson's poem,
the lady leaves her secluded shadowy world to find enter the real world that Lancelot
inhabits.  She dies before she reaches Camelot and meets
Lancelot.

Both involve the contrasting worlds of
imagination and reality.  Keats' knight after experiencing the extraordinary world of
the imagination cannot bear the dullness of the real world; Tennyson's lady, after only
knowing the shadowy secluded world of fantasies, cannot survive in the bright world of
reality.