The old nursery rhyme 'There was an old woman of Leeds' is believed to refer to a woman called Sarah Keighley. Sarah Keighley was a pious woman, from the English town of Leeds. She had strong Calvinistic principles and was the aunt of the American theologian Joseph Priestley (1733-1804). Priestley is usually remembered for his 1774 discovery, in England, of oxygen. Priestley left England for a new life in Pennsylvania where he counted Benjamin Franklin, Thomas Jefferson, and James Watt amongst his friends..