The Amenemhet I pyramid at El-Lisht.
Amenmehet I was a vizier of Mentuhotep IV of the previous dynasty. He was not of royal descent. He is thought to have overthrown Mentuhotep IV and founded the 12th dynasty.
The 12th dynasty lasted almost 200 yrs and was essentially the Middle Kingdom of Egypt.
The pyramids of the 12th dynasty characteristically had a core that was made out of mudbricks and an external veneer that was made from limestone.
A large slave labour force was needed to make the mudbricks.
A workers village was found by Petrie in 1891 at Kahun. He found scarabs from the time of Sensuret II that indicated that it was occupied during the 12th dynasty up until the 13th dynasty. He also found evidence of a sudden exodus from the village in the 13th dynasty. He thought that many of the semitic slaves were Isralites.
Joseph came to Egypt at the age of 30 yrs and was 110 yrs when he died. The Jews lived in Egypt 430 years and then Moses lead them out of Egypt (The Exodus). The Israelites numbered only 70 when they came to Egypt in the ?third dynasty. By the 12th dynasty, they numbered over a million and the pharaoh had long forgotten their connection to Joseph (?Imhotep) who had saved Egypt from famine and may even have built the first pyramid.
Amenemhet I – the first pharaoh of the 12th dynasty. He reigned for 30 yrs (including a 10 yr coregency with his son Sensuret I) and then was assassinated.