I doubt if she was a princess as her absence from mother England would be carefully documented. It is possible that she may have been a daughter of a noble or gentleman. Possibly she was a lady-in-waiting for a princess. Such women were drawn from the ranks of the nobility anyway. The name "Mary Lewis" sounds sufficiently prosaic to obscure what may have been her true identity. As for the "Egyptian", well possibly anyone of colour in those times could qualify for an "Egyptian". However, it does hint of a "gypsy" - a name derived from "EGYPtian" in the days when it was thought that that was the homeland of these people, not northwest India as we now know). If he was a man of colour, would pre Civil War USA be the place to which to escape? I doubt it. A website called The Peerage - www.thepearage.com
- is the most comprehensive collection of British aristocratic genealogies I know of. You could also do word searches of the fine British newspapers now available online from the period, eg British Newspaper Archive, and do word searches. But you may have a long slog. I have been trying to solve the riddle of my own, apparently blueblood, ancestor for several decades but it is painfully slow business. You can see my post at: http://boards.ancestry.com/topics.royalty.britisles/433/mb.a...
Hope this helps a bit
Mark St Leon