This is a portrait of Sir William Douglas-Hamilton, The Duke of Hamilton (1730-1803). Sir William Douglas-Hamilton was the brother inlaw of my paternal 1st cousin, 10x removed, General Robert Clerk (1723-1797) who married Lady Elizabeth Hamilton (1720-1800).

 

Sir William was the fourth son of Lord Hamilton, Governor of Jamaica. Sir William was a diplomat, antiquarian, archeologist and a volcanologist. Between 1764-1800 he served as England's ambassador to the Court of Naples.

 

More information is available about Sir William at the following links:

 

https://en.wikisource.org/wiki/Hamilton,_William_%281730-1803%29_%28DNB00%29

 

http://www.douglashistory.co.uk/history/williamdouglashamilton.htm