My first can boast a head and tail

My first can boast a head and tail, Has feathers and an eye, And sometimes wings; yet what avail? It cannot walk or fly.

And St. Paul was my first, we ’re told; And my first may be bought In bottles,—but though rare and old, Its value ’s almost naught.

Out of my last my first is made, My last is in a crown; And heroes wield its shining blade For glory and renown.

My whole, a marvel of brute force With human power combined; We never see it now, of course, We ’ve left it far behind.