Hey Flash... Dr. Fate has had a diverse career in the DC Universe and I personally believe the Golden Age Doctor Fate is the best version. To make a long story short, a 12-year old Kent Nelson was on an archaeological dig with his father Sven in the Valley of Ur.
Unbeknown to them both and while exploring, they released an ancient gas that held Nabu, a godlike being in status which killed Sven Nelson. Nabu was an Egyptian Wizard and also a Lord of Order from another realm with godlike powers. The Lords of Order fought a never ending battle against the Lords of Chaos and Nabu protected Earth.
Depending on which origin you read, Nabu wiped the memory of Sven's death from Kent and trained him in the mystic arts. Years passed and when Kent became a man (or Nabu aged him to adulthood), the Lord of Order removed the mind wipe from Kent which forced Kent to destroy Nabu's mortal shell in rage.
Nabu as an energy being explained what he had done and then gave Kent the mystic artifacts of Dr. Fate which was the Helm of Nabu, the Cloak of Destiny and the Amulet of Anubis. Kent donned the items and became Dr. Fate who waged war on the Lords of Chaos and their agents on Earth.
These two images sum up his history rather well...