Envoy Extraordinary to the Kingdom of the Two Sicilies, William Hamilton (1730–1803) William Hamilton (1730-1803) was a British diplomat who served as Envoy Extraordinary to the Kingdom of the Two Sicilies whose capital was Naples. Present for the eruptions of Mount Vesuvius during the mid-to-late eighteenth century, Hamilton wrote Campi Phlegraei in two parts, with a tertiary supplement, based on his 1772 Observations on Mount Vesuvius for the Royal Society. Published in French and English, he hired local artist Pietro Fabris to illustrate it. These images are colored etchings after gouaches by Fabris. They are taken from a recent post from publicdomainreview.org with the etchings being part of the Wellcome Collection.