The German for bath or spa is Bad. I thought Baden must be the plural but that appears to be Bäder. So what's Baden? Bathing? Bathing-Bathing?

Ronnie Barker did a sketch in The Two Ronnies about people who had a speech impediment making them say things twice. Of course he has it too. In his appeal he says, "So instead of saying Baden-Baden-Baden-Baden, they say Baden-Baden-Baden-Baden-Baden-Baden-Baden-Baden." :-)

Just the other day I found a fascinating site on dynasties: http://www.hostkingdom.net/regindex.html. It says there the Margravate of Baden was divided in 1190 into Baden-Baden (the elder line) and Baden-Hachberg. It gets rather confusing around 1335, but I think Baden-Baden was partitioned into Baden-Pforzheim and Baden-Eberstein. And it all went downhill from there.

My guess is that Baden the town was the original capital of Baden the territory, and whenever it was divided it was called Baden-<capital>, so B-B was the one that kept B.