Percy Shelley's "Triumph of Life" was his last major poem. He drowned before he could finish it. It is, in a way, a tribute to the poet Dante Aligheri, written in terza rima, just as is Dante's Commedia. Its main theme is the nature of being and how life has a way of ultimately corrupting the spirit, even of those we consider to be great. In the lines you have asked about, Shelley (the narrator or speaker of the poem) is describing a vision of a chariot and groups of people, particularly some of the famous people he sees passing by him in his waking dream. He describes kings and rulers and tells how life conquered all of them despite their accomplishments and achievements. Thus, Life triumphs over everything in the end. There are no similes in the lines you mention.