One of the links between the two subjects of our first assignment was the image of the swan. In Yeats, this crops up in many phases of his poetry, but in his late work it comes to represent a kind of nobility and pride, and even the soul itself. In the Tower he speaks of the dying hour:

When the swan must fix his eye
Upon a fading gleam,
Float out upon a long
Last reach of glittering stream
And there sing his last song.
WB Yeats, The Tower, 1928

He returns to this vision to conclude the poem, with the image of ‘a bird’s sleepy cry/Among the deepening shades.’

In Leda and the Swan it embodies divine power and knowledge, and Yeats emphasises the swan’s physical force:

A sudden blow: the great wings beating still
Above the staggering girl…
WB Yeats, Leda and the Swan

Compare this to his treatment of the swan in another great poem from his later period:

At sudden thunder of the mounting swan
I turned about and looked where branches break
The glittering reaches of the flooded lake.
WB Yeats, Cool Park and Ballylee, 1931

Yeats’s imagery here is not flat or two dimensional, but rather a living, breathing power – we feel the swan in all the ‘vigour and turbulence of the flesh’ (Stan Smith’s phrase).

Regarding the Sibelius symphony, he has described how it was inspired by the sight of sixteen swans in flight near his home in Finland. He wrote about it in a letter during its composition:

One of my greatest experiences. Lord God, that beauty! Their call, the same woodwind type as that of cranes, but without tremolo. The swan call, closer to the trumpet, although there is something of a sarrusophone sound. A low refrain, reminiscent of a small child crying. Nature, mysticism and life’s angst. The 5th Symphony’s finale theme: Legato in the trumpets!!
Jean Sibelius, Letters

He later said that on laying down his pen after finally finishing the 5th Symphony, twelve white swans settled down on the lake outside his home, and then circled the house three times before flying away.