The ruling abbesses
First little gem from the Mediev-L email list, the information that there were German mini-states ruled only by women (abbesses) for hundreds of years.
"...the female abbey of Essen which lasted 873-1803, and was I believe territorially the largest of them. ... The bucolic town of Essen was founded in the tenth century by the abbess Hedwig I. ... It became a principality of the empire in 1275. The ruling abbess was assisted by a chapter of ten other nuns, who were largely aristocratic...
Here is a snip from the 14th century.
Kunigunde II of Berg 1328-1336
Katarina of La Marck 1336-1360
Irmgard II of Bruch 1360-1370
Elizabeth III of Nassau 1370-1412"
I'm keen to find a source to find out more. (In English - can't do German, sorry!)