Harry Clarke was one of the great stained-glassed window artists of all times. This DVD discusses his life. There are many books on him. He mainly lived in Ireland but worked in Sydney Australia for a time and constructed stained glass windows at University of Sydney and in churches around Sydney. He also did A. Beardsley style illustrations for books such as those creepy novels by Edgar Allen Poe. I am told by one section of my family that he was my father’s 'grandfather' but other segments disagree.
I traced my Irish-based family tree back to the voyages my ancestors took out here in the 19th century (yes, one wicked line came here with a chain around one leg) but I never could nail the ancestry thing down.
The old Harry Clarke however was a great artist however and I am happy to bask - legitimately or not - in his reflected glory and to bear his name. Some good pics done by the old HC here.
Postscript: As I have now determined there is (apparently) no relationship here at all. My ancestors were Protestant from Ireland and as FXH points out this famous Harry Clarke was trained by the Jesuits. The Harry Clarke that I am related to was a minor artistic figure who lived for a time in Petersham NSW and who did a number of stained glass windows around Sydney's inner west and, I believe, at the University of Sydney.