The correct answer is the Dark Age.
The period after the collapse of the Mycenaean civilization is called the Dark Age.
The time that is considered the Greek Dark Age is about 1200 BCE. The spam of the Dark Age period run after the collapse of the Mycenaean civilization until what is considered the Greek Archaic Period, about 800 BCE. Some historians believe that this Dark Age was also an early Iron Age because of the archaeological discoveries of iron tools in the region. All of the buildings and structures of the Mycenaean civilization were destroyed. Archaeologist only could find burials and pieces of pottery.