How long, for how many centuries, did the kingdom of Ancient Egypt last?
This is a difficult question, as it depends on what you define as the Kingdom of Egypt, as many different dynasties have existed in Egypt. The first known ruler of Egypt was the Pharaoh Menes, who lived from around 3150 BC to 3100 BC. Many different families then took control of the Egyptian throne until the arrival of Alexander the Great, who seized control of the country in 332 BC and after his death the family of the Ptolemies took over as kings of the country.
This family line lasted almost 300 years until the death of Cleopatra, the last pharaoh of Egypt. For centuries Egypt was then kept under Roman rule and was administered by Roman officials. It was then overtaken in the 6th century AD by Arabic invaders who established a series of caliphates and sultanates.
The last true monarch of Egypt was overthrown in 1952, which is the full and formal end to the monarchy of Egypt. Many scholars define the Kingdom of Ancient Egypt as lasting from 3150 BC to 30 BC, but this can be debated, altered and changed for many separate and conflicting reasons.