Ancient Greek Government and Law. The Ancient Greek world had no single system of law; individual states like Athens and Sparta, instead created their own political and legal ideas. The most common systems of Greek government were Democracy - where the people made the decisions. Monarchy - rule by one individual who had inherited his role, much like a King. Oligarchy - rule by a small group of people.Designed for classroom | home | distance learning and aimed at children and young adults who are