Dreamer of Dreams

(Stumbled on this poem from this site, where it was just two lines at the bottom of the page, but after that it has been stuck in my head. It is what can be called a poet's poem. What haunts me the most is the last two lines. )

We are the music-makers,
And we are the dreamers of dreams,
Wandering by lone sea-breakers,
And sitting by desolate streams.
World-losers and world-forsakers,
Upon whom the pale moon gleams;
Yet we are the movers and shakers,
Of the world forever, it seems.

With wonderful deathless ditties
We build up the world's great cities,
And out of a fabulous story
We fashion an empire's glory:
One man with a dream, at pleasure,
Shall go forth and conquer a crown;
And three with a new song's measure
Can trample an empire down.

We, in the ages lying
In the buried past of the earth,
Built Nineveh with our sighing,
And Babel itself with our mirth;
And o'erthrew them with prophesying
To the old of the new world's worth;
For each age is a dream that is dying,
Or one that is coming to birth.

-Arthur O'Shaughnessy.