The Mummy franchise traces its roots to the 1930s, when Boris Karloff portrayed the historic embalmed character at the height of the Universal Classic Monsters heyday. The first film, made in 1932, framed Imhotep as a mummy carrying an ancient curse. But Imhotep was a real-life priest in ancient Egypt, and he wasn't anything like his character in The Mummy movies.
So who was Imhotep? The real Imhotep was one of the first recorded geniuses in world history. He was an engineer, a physician, a politician, and a priest. Over the course of his life, he worked his way through the Egyptian ranks to hold a key position in the governments of two different pharaohs. He was also the mastermind behind the first pyramid.
By contrast, the Imhotep of The Mummy remake is a lovesick megalomaniac who plots against the Pharaoh out of his love for the queen. Thousands of years later, he rises from the grave to wreak havoc on the world and bring his love back to life. He causes plagues, levels cities, and defies the afterlife. The real Imhotep was impressive, but he wasn't quite capable of such supernatural feats.
Imhotep became the High Priest of Ptah (the god of craftsmen) during the reign of King Djoser and was responsible for the construction of the king's burial place. Previous royal tombs had been simple rectangular structures, but Imhotep decided to create a brilliant final resting place for King Djoser.
Using a number of architectural innovations, Imhotep built the Step Pyramid of King Djoser, which was the tallest structure in the world at the time of its construction. The king was so pleased with Imhotep's work that he allowed the priest's name to be inscribed on the pyramid along with his own.
The Imhotep of The Mummy franchise isn't so much interested in building pyramids as he is in looting them for artifacts and exploiting their ancient supernatural qualities. In The Mummy Returns, Imhotep travels to the pyramid of the Scorpion King to face off against the ancient leader and gain command over the ghastly legions of Anubis.
Ptah was an important god in the ancient Egyptian pantheon. He was the god of craftsman and architects, roughly analogous with the Greek god Hephaestus or the Roman god Vulcan. However, Ptah was also the patron god of Memphis. When Memphis became the seat of government, Ptah's followers grew numerous and powerful.
Imhotep quickly worked his way through the ranks to become High Priest of Ptah, earning a place in the highest government councils. At that point, a priest's role was both religious and civil. Imhotep's priestly position gave him oversight of earthly matters, such as the construction of the first pyramid.
In the movies, Imhotep is still a High Priest, but his ambitions aren't limited to this world. After being entombed in a sarcophagus, he is awakened in the modern world and sets out to become a god himself, first by resurrecting his lost love and then by trying to defeat the Scorpion King.
Everyone gives the Romans a hard time for co-opting the Greek gods, but the Greeks weren't above a little appropriation themselves. Thoth, the Egyptian god of the moon, became identified with Hermes, while Imhotep himself was associated with Asclepius, the god of medicine.
Meanwhile, the evil Imhotep of The Mummy franchise is out here trying to become a different kind of god entirely. In the movies, Imhotep is identified constantly with Anubis, the jackal-headed god of embalming. In the climax of The Mummy Returns, Imhotep struggles for control of Anubis's jackal-headed troops that guard the Scorpion King's pyramid.
The film version of Imhotep meets his end after plotting against the Pharaoh. He is buried alive in a sarcophagus under a statue of Anubis. In real life, Imhotep followed a different path to immortality. Almost two thousand years after his passing, around 525 BCE, he was deified by the Egyptian people and worshipped as the god of healing.
He is one of only two common Egyptians to be given this honor. Strangely enough, the other deified commoner, Amenhotep, was also a healer.