Ozymandias is another name for Ramesses the Great, one of the greatest Pharoahs of Ancient Egypt, who lived in the 14th century B.C. Shelley's poem is based on an actual inscription on the base of a statue of Ramesses, as reported by a Greek Historian, in the first century B.C.
I met a traveler from an antique land,
Who said, "Two vast and trunkless legs of stone
Stand in the desert. Near them, on the sand,
Half sunk, a shattered visage lies, whose frown,
And wrinkled lip, and sneer of cold command,
Tell that its sculptor well those passions read,
Which yet survive, stamped on these lifeless things,
The hand that mocked them and the heart that fed:
And on the pedestal these words appear:
'My name is Ozymandias, King of Kings.
Look on my works ye Mighty, and despair!'
No thing beside remains. Round the decay
Of that Colossal Wreck, boundless and bare,
The lone and level sands stretch far away."
—Percy Bysshe Shelley