The position of the nomarch was at times hereditary, while at others nomarchs were appointed by the pharaoh . The balance of power between nomarchs and the central government varied from one pharaoh's rule to the next. Generally, when the national government was stronger, nomarchs were appointed governors. But when the central government was weaker – at times of foreign invasion or civil war, for example – rulers of individual nomes would assert themselves and establish hereditary lines of succession. Conflicts between these different hereditary nomarchies were common during, for example, the First Intermediate Period – a time that saw a breakdown in central authority lasting from the sixth to the eleventh dynasty, until one of the local rulers, Mentuhotep of Thebes, was able to assert his control over the entire country as pharaoh.
The division of the kingdom into nomes can be documented as far back as the Old Kingdom (in the 3rd millennium BCE) and continued even up until the Roman period.