The key to understanding the passage in lines 126 through 134 of Shelley's "The Triumph of Life " lies in the lines that surround the passage and give both background and explanation to the passage--by itself, the passage is pretty much incomprehensible. The full context really extends from "And...
The key to understanding the passage in lines 126 through 134 of Shelley's "The Triumph of Life" lies in the lines that surround the passage and give both background and explanation to the passage--by itself, the passage is pretty much incomprehensible. The full context really extends from "And o'er what seemed the head, a cloud like crape, ..." to "Oft to new bright destruction come & go. ..." The most immediate context extends from
When Freedom left those who upon the free
Had bound a yoke which soon they stooped to bear.
Nor wanted here the true similitude
Of a triumphal pageant, for where'er
The chariot rolled a captive multitude
to the lines, past the excerpt of your question, that read:
Were neither mid the mighty captives seen
Nor mid the ribald crowd that followed them
Or fled before . . Now swift, fierce & obscene
The wild dance maddens in the van, & those
Who lead it, fleet as shadows on the green,
Outspeed the chariot & without repose
Mix with each other in tempestuous measure
To savage music
It is only in context that this passage of Shelley's dream vision are to be understood. We can see that the four faced charioteer ("four faces of that charioteer") drove "a captive multitude" before the chariot. We are told of what sorts of people this multitude is comprised, such as aged rulers or aged sufferers (odd juxtaposition ...), those who suffer to the last moment of their lives, those with either fame or infamy, etc. We are then told of those who do not comprise the captive multitude. These are specifically "the sacred few" who being born, die immediately and "like eagles" flee back to whence they came:
As they had touched the world with living flame
Fled back like eagles to their native noon,
It is these who are identified as being "they of Athens & Jerusalem" who are neither among those who comprise the captives nor those mocked the captives. In summary, the passage you ask about identifies the "sacred few" who are neither captive nor mockers of the captives; mockers "whose unholy leisure / Was soothed by mischief since the world begun, ...." The metaphor of "sacred few" relates to those who die as infants; the metaphor of "mockers" relates to the wicked of Earth, or even wicked demons.