|Lo! in the orient when the gracious light,|
Lifts up his burning head, each under eye,
|Doth homage to his new-appearing sight,|
Serving with looks his sacred majesty;
|And having climbed the steep-up heavenly hill,|
Resembling strong youth in his middle age,
|Yet mortal looks adore his beauty still,|
Attending on his golden pilgrimage:
|But when from highmost pitch, with weary car,|
Like feeble age, he reeleth from the day,
|The eyes, 'fore duteous, now converted are|
From his low tract, and look another way:
|So thou, thyself outgoing in thy noon|
|Unlooked on diest unless thou get a son.|
(from Shakespeare's Sonnets.com)
The poet explores another theme, different from those he has pursued in the preceding sonnets. He draws a simile between the rising and setting sun and youth and age. In the sunset of his days the youth will no longer be surrounded by admirers. Unless he has children to carry on the line and reflect his former beauty, he will vanish unknown into the murky depths of time.When the sun rises, everyone admires it, and pays homage to it, as if it were a king. As it climbs higher in the sky to reach its zenith, mortals admire it still. But as it plunges downwards towards evening, the gaze is averted, and, like 'unregarded age in corners thrown', it is ignored and other rising stars take precedence. 'So you too, fair youth, will be nothing as you age, unless you become the rising sun by having a son.'
the gracious light = the sun. The Eastern lands are also suggested, where, in places, the sun was worshipped. The sun is considered kingly among the heavenly bodies in the old Ptolemaic astronomy. gracious = noble, glorious, kind etc.
each under eye = each dweller on earth, under the sun. But from what follows it is clear that the reference is also to inferior beings in the social scale, those who gaze in awe on kings.
For as the sun is daily new and old 76.
steep-up = inclined steeply upwards.
weary car = weary chariot of the sun (in practice the horses which pulled it would be weary, having climbed the steep up heavenly hill). For a classical depiction of the sun's chariot see illustration below. The horses of the sun are also featured in the Elgin marbles from the Parthenon.
now converted are = now are turned away, averted. To convert did not then have the predominant meaning of 'to cause someone to change faith'.
tract = pathway, track. The sun is now low in the sky, ready to plunge once more beneath the horizon.