Leonard Walter de Courtenay, born about 1831

fname=Elisabeth
lname=Roeder-Voss
address1=Altvolberg 20
address2=
city=Roesrath
state=Germany
country=
zip=51503
eroeder@web.de
ancestor=Again: Leonard Walter de Courtenay, born abt 1831
comments=Birth year calculated because of confirmation in 1845. Photograph by Abdullah Freres, Constantinoples, may have been taken during world exposition in Paris, 1867, looks like man in his thirties, too.
He was a relative to my ancestress Lavinia Sally Anne DUBOURDIEU in Stade, Hannover, Germany. She mentioned him in her last will and testament, and he was obviously very close to her. But I still don't know just how they were related. He might have been her grandson or even great-grandson ...
She was Lavinia Sally Anne HARFFY, born most probably in Canada in 1772 (daughter of Dr. William HARFFY).
Married in 1789 William GRAHAM (GRAHAM OF NETHERBY), captain in 65th regt of Foot, brother of Sir James GRAHAM, 1. baronet of Netherby. They lived in Marylebone. William GRAHAM died in 1792, leaving a son, Robert Charles GRAHAM. (Daughter Lavinia Frances must have died in infancy.) Robert Charles had a daughter Caroline Agnes GRAHAM, born 1813.
Lavinia returned to Canada (about 1794/96) and married Robert COOPER, Lieutenant Royal Engineers, who died Jan. 1799 in Quebec.
Daughter: Catherine Johanna Louisa COOPER, bapt. Arthuret, Cumberland, Sep 1799, m. in 1828 to the Hannoverian officer George Franz VON HASSELL.
In 1811 she married again (St. Anne, Soho, London): Francis DUBOURDIEU, of an Irish Huguenot family, Hanoverian Engineers, with whom she went to Hannover. She died in Oerel, Hannover, in 1853.
Any help will be much appreciated.
Elisabeth Roeder-Voss