ThePeerage.com is a fascinating, ever-expanding database of the nobility and peerage of Britain and the royal families of Europe.
This website is a labor of love "by one (somewhat eccentric) person collecting information on the European royal families and on the British Peerage, and then entering it into a range of various genealogy programs."
It is possible to search by surname, and also to follow the links back through the generations by clicking on each ancestor.
There is also a Master Index, a Place Index, discussion group, and helpful FAQ. Click on "custom index" to sort the place names by country.
Contact the compiler, Darryl Lundy, via email email@example.com or via the site's discussion group with any corrections and additional data.