His relationship to the heretic king Akhenaten almost certainly caused the downfall and possibly the death of the young king Tutankhamun. For his short reign of only nine years seems to have been taken up with rectifying the chaos and errors bequeathed to him by Akhenaten.
Tutankhamun or as he was first called Tutankhaten, was born in a time of great change and upheaval. The 18th Dynasty of Egypt had, until the reign of Akhenaten, been a prosperous one. The Pharaohs had been great warriors. They had added to their country's wealth, and added to Egypt's territories, from which came valuable minerals and particularly gold.
Akhenaten was the complete antithesis of these early kings. He was not a warrior, he was a dreamer and philosopher more interested in theoretical theology and the arts, than in mastering the art of kingship.
He brought in great changes to a conservative land. He introduced the worship of the sun-disc, the Aten, as the official religion, removing the royal patronage from the god and priests of Amun. He moved the capital from Thebes and established a new capital 240 miles to the north, which he called Akhetaten "The Horizon of the Aten". He neglected to secure Egypt's borders, and chaos broke out, vassal princes broke away and the economy fell into ruins. Thus at his death, he had the establishment, the priesthood, and the people against him.
It was against this background that Tutankhamun succeeded to the throne. In line with Egyptian tradition he secured his position by marrying his half sister (or sister or other relation, depending on which theory is correct) Ankhesenpaaten, the third daughter of Akhenaten and Nefertiti.
His first three years as king were spent at Akhetaten, during which time his relative Ay, as regent, tried to rectify the errors perpetrated by Akhenaten. To return to stability, it was necessary to return to the old order, and eventually during the third year of Tutankhamun's reign the court re-established itself again at Thebes, where the young king was crowned.
The old religion of Amun was restored and the king changed his name from Tutankhaten to Tutankhamun, his wife changing her name from Ankhesenpaaten to Ankhesenamun. For the next few years, attempts were made to put right everything that Akhenaten had done wrong. Egypt gradually settled back to stability....almost. We have very little evidence of what really went on at the time. But suddenly, and quite unexpectedly, in the young king's eighteenth year, he died.