The 1st Intermediate Period of ancient Egypt began when the Old Kingdoms centralized monarchy grew weak as provincial rulers called nomarchs became powerful, and ended when the Theban monarch gained control of all Egypt.
The Old Kingdom is described as ending with the longest-reigning pharaoh in Egyptian history, Pepy II.
After him, building projects in the cemeteries around the capital of Memphis stopped. Building resumed at the end of the 1st Intermediate Period, with Menhotep II at Deir el-Bahri in western Thebes.
Egyptian intermediate periods are times when the centralized government weakened and rivals claimed the throne. The 1st Intermediate Period is often characterized as chaotic and miserable, with degraded art -- a dark age. Barbara Bell* hypothesized that the 1st Intermediate period was brought about by a prolonged failure of the annual Nile floods, leading to famine and collapse of the monarchy.
[*Barbara Bell: The Dark Ages in Ancient History. I. The First Dark Age in Ancient Egypt. AJA 75:1-26.]
But it was not necessarily a dark age, even though there are bragging inscriptions about how local rulers were able to provide for their people in the face of great adversity.
There is evidence of thriving culture and the development of towns. Non-royal people gained in status. Pottery changed shape to a more efficient use of the pottery wheel. The 1st Intermediate Period was also the setting for later philosophical texts.
During the 1st Intermediate Period, cartonnage was developed.
Cartonnage is the word for the gypsum and linen colored mask that covered the face of a mummy. Earlier, only the elite had been buried with specialized funerary goods. During the 1st Intermediate Period, more people were buried with such specialized products. This indicates that the provincial areas could afford non-functional craftsmen, something that only the pharaonic capital had done before.
Not much is known about the early part of the 1st Intermediate Period. By the second half of it, there were two