Around 3100 b.c. the kingdoms of Upper and Lower Egypt were unified under King Menes  his crown was the first to depict the symbols of both kingdoms.
3100 b.c. was the first time all of Egypt was united under one ruler.
mnli hypothesis: 3100 b.c. was the first time all of Egypt was united under one ruler. premise: Around 3100 b.c. the kingdoms of Upper and Lower Egypt were unified under King Menes  his crown was the first to depict the symbols of both kingdoms.