Written in a sonnet with loose iambic pentameter. Iambic pentameter is pairs (iams, of sounds da-dum)
with 5 (pentameter, think of pent like in pentagon) in a line making 10 syllables overall.
Sonnets were generally popular romantic or love poems, perhaps this being a love poem about Ozymandias, a joke about the
rulers ego. Or simply to capture the romantic and exotic tone of a lost legend.
The Rhyme scheme is irregular, perhaps symbolic of the broken statue itself, no longer perfect.