Complex sentence: The ten cities were not an official league or political unit, but they were grouped together because of their language, culture, location, and political status, with each possessing a certain degree of autonomy and self-rule.
Split into simpler sentences: The ten cities were not an official league or political unit, but they were grouped together because of their language, culture, location, and political status. Each city had a certain degree of autonomy and self-rule.