Henry Wadsworth Longfellow
The Castle-Builder
A gentle boy, with soft and silken locks
  A dreamy boy, with brown and tender eyes,
A castle-builder, with his wooden blocks,
  And towers that touch imaginary skies.
A fearless rider on his father's knee,
  An eager listener unto stories told
At the Round Table of the nursery,
  Of heroes and adventures manifold.
There will be other towers for thee to build;
  There will be other steeds for thee to ride;
There will be other legends, and all filled
  With greater marvels and more glorified.
Build on, and make thy castles high and fair,
  Rising and reaching upward to the skies;
Listen to voices in the upper air,
  Nor lose thy simple faith in mysteries.