What is the theme and some of the literary devices used in Percy Bysshe Shelley's poem "Ozymandias"?

The might and majesty of a king do not last; only great art endures. The statue, symbolizing the power and glory of the pharaoh, is crumbling. Yet the arrogant sneer on the "shattered visage" remains intact as a testament to the ability of the sculptor to read and capture the passions of his ruler. Thus, it is the pharaoh's lowly servant, the sculptor, who delivers the more powerful message here. The king's message—"look on my works, ye Mighty, and despair"—is an ironic indictment of his pride.
.......Oddly, Shelley's theme—valid as a general statement—does not ultimately apply to Ozymandias, or Ramses II. For Ramses remains today perhaps the most famous of Egyptian pharaohs. After thousands of years, he continues to intrigue historians, archeologists, and other scholars.
.......In addition, many of the monuments erected during his rule still stand.