Edward John Trelawny’s Records of Shelley, Byron, and the Author is, according to blogger Pykk:
a gossipy, wayward, autobiographical book by a moustach’d Romantic who tracked down both poets in 1822 and stayed with them for a while by the Mediterranean. He was still there when Shelley died, and alert enough to rescue the poet’s unburnt heart from his funeral pyre. The cremation, though romantic on paper, was not a romantic gesture; the body had to be carried from the shoreline where it was found to Rome for burial, and the authorities, fearing infectious disease, weren’t going to let them travel through the countryside with an intact corpse.
“In snatching this relic from the fiery furnace,” Trelawny writes, “my hand was severely burnt; and had anyone seen me do the act I should have been put into quarantine.” The heart was passed on to Mary Shelley, who wrapped it in a copy of her husband’s Adonaïs and deposited it in a box on her desk.