Janus

Janus am I; oldest of potentates;
  Forward I look, and backward, and below
I count, as god of avenues and gates,
  The years that through my portals come and go.

I block the roads, and drift the fields with snow;
  I chase the wild-fowl from the frozen fen;
My frosts congeal the rivers in their flow,
  My fires light up the hearths and hearts of men.

-- From "The Poet's Calendar (January)," by Henry Wadsworth Longfellow