Because your question searches for deep meaning, I shall explain in simple words

The customs and fashions of men change like leaves on the bough, some of which go and others come.

He whom you see-along the downward arc- was William, and the land that mourns his death, for living Charles and Frederick, now laments; now he has learned how Heaven loves the just ruler, and he would show this outwardly as well, so radiantly visible.

But the stars that marked our starting fall away. We must go deeper into greater pain, for it is not permitted that we stay.

Worldly fame is but a breath of wind that blows now this way, and now that, and changes name as it changes direction.

Because your question searches for deep meaning, I shall explain in simple words

Lying in a featherbed will bring you no fame, nor staying beneath the quilt, and he who uses up his life without achieving fame leaves no more vestige of himself on Earth than smoke in the air or foam upon the water.