The four sons of Horus were a group of four gods in Egyptian religion, who were essentially the personifications of the four canopic jars, which accompanied mummified bodies. Since the heart was thought to embody the soul, it was left inside the body. The brain was thought only to be the origin of mucus, so it was reduced to liquid, removed with metal hooks, and discarded. This left the stomach (and small intestines), liver, large intestines, and lungs, which were removed, embalmed and stored, each organ in its own jar. There were times when embalmers deviated from this scheme: during the 21st Dynasty they embalmed and wrapped the viscera and returned them to the body, while the Canopic jars remained empty symbols.
The earliest reference to the sons of Horus the Elder is found in the Pyramid Texts where they are described as friends of the king, as they assist the king in his ascension to heaven in the eastern sky by means of ladders. Their association with Horus the Elder specifically goes back to the Old Kingdom when they were said not only to be his children but also his souls. As the king, or Pharaoh was seen as a manifestation of, or especially protected by, Horus, these parts of the deceased pharaoh, referred to as the Osiris, were seen as parts of Horus, or rather, his children, an association that did not diminish with each successive pharaoh.
Since Horus was their father, so Isis, Horus's original wife in the early mythological phase, was usually seen as their mother, although Hathor was also believed to be their mother, though in the details of the funerary ritual each son, and therefore each canopic jar, was protected by a particular goddess. Others say their mother was Serket, goddess of medicine and magic. Just as the sons of Horus protected the contents of a canopic jar, the king's organs, so they in turn were protected. As they were male in accordance with the principles of male/female duality their protectors were female.
The classic depiction of the four sons of Horus on Middle Kingdom coffins show Imsety and Duamutef on the eastern side of the coffin and Hapi and Qebehsenuef on the western side. The eastern side is decorated with a pair of eyes and the mummy was turned on its side to face the east and the rising sun; therefore, this side is sometimes referred to as the front. The sons of Horus also became associated with the cardinal compass points, so that Hapi was the north, Imsety the south, Duamutef the east and Qebehsenuef the west. Their brother was Ihy, son of Hathor.