Seven worlds were founded in TE 37 to serve as bases for Imperial expansion. These seven, along with Earth, became the capitals of the eight Imperial Provinces.
Each Province was ruled by a Duke/Duchess. In theory, a Duke/Duchess was appointed by the Imperial Council (and later the Emperor), but in practice they were basically hereditary positions. (Maj Thovold, however, did change some of the appointments, and the ability to make and un-make Dukes/Duchesses remained a perogative of the Throne, albeit a little-used one.)
The eight Provincial Capitals were: