The dates of the Predynastic period were first defined before widespread archaeological excavation of Egypt took place, and recent finds indicating very gradual Predynastic development have led to controversy over when exactly the Predynastic period ended. Thus, the term "Protodynastic period", sometimes called the "Zero Dynasty", has been used by scholars to name the part of the period which might be characterized as Predynastic by some and Early Dynastic by others.