Percy Bysshe Shelley's poem Ozymandias is written in iambic pentameter and contains the famous lines
'My name is Ozymandias, king of kings:
Look on my works, ye Mighty, and despair!'
I can think of a few different ways that the name Ozymandias could be proncounced, but all of them have five syllables. However, to fit the meter it should be only four syllables. Wikipedia gives "oz-ee-mand-yəs" as a 4-syllable pronunciation, but to me as a modern British English speaker this feels kind of forced.
My question is whether a four-syllable pronunciation would have been more natural in the 1810s when the poem was written, and if so, what that pronunciation would have been.
At one point I thought it might be a linguistic trick, in which Ozymandias' hubris is so great that he demands an extra syllable in his line, but the Wikipedia page also includes a poem by Horace Smith at around the same time, which is also in iambic pentameter and contains the line
"I am great OZYMANDIAS," saith the stone,
This also requires "Ozymandias" to have four syllables, suggesting that the extra syllable isn't a quirk of Shelley's poem.
To reiterate, this question is about how the name "Ozymandias" would have naturally been pronounced in Shelley's time. Many comments and answers say that the extra syllable can be elided or unstressed, which is fair enough. However, I'm interested in how it would have been pronounced historically. Would Shelley and Smith have seen it as an extra-metrical syllable that they would have elided or un-stressed in order to fit it to the meter, or would they simply have thought of "Ozymandias" as being a four-syllable word in the first place, with the modern five-syllable pronunciation being due to a shift that occurred afterwards? I'm looking for answers that concretely address the historical pronunciation.