Horus is a god of the Ancient Egyptian religion, most commonly known by the Greek version Horus, of the Egyptian Heru/Har. Horus was an ancient and important deity. He was also the son of Isis and Osiris. Some details of the character are changed or intermixed with other characters throughout the different dynasties and Egyptian cults and religions. For example, when Heru (Horus) fuses with Ra the Sun God, he becomes Ra-Horakhty.

The Eye of Horus became an important Egyptian symbol of power. Horus had a man's body and a falcon's head. Horus fought with Seth for the throne of Egypt. In this battle one of his eyes was injured and later it was healed by Isis. This healing of the eye became a symbol of renewal. Horus united Egypt and bestowed divinity upon the pharaohs who were viewed as incarnations of Horus in life.

Sky god

Horus was told by his mother, Isis, to protect the people of Egypt from Set, the god of the desert, storms and chaos.

Since he was god of the sky, Horus became depicted as a falcon, or as a falcon-headed man, leading to Horus' name, (in Egyptian, Heru), which meant The distant one. As falcon he may be shown on the Narmer Palette dating from the time of unification of upper and lower Egypt. Horus was also sometimes known as Nekheny (meaning falcon), although it has been proposed that Nekheny may have been another falcon-god, worshipped at Nekhen (city of the hawk), that became identified as Horus very early on. He was married to Hathor, the god of love. In this form, he was sometimes given the title Kemwer, meaning (the) great black (one).
Horus represented in relief with Wadjet and wearing the double crown - temple of Hatshepsut

As Horus was the son of Osiris, and god of the sky, he became closely associated with the Pharaoh of Lower Egypt (where Horus was worshipped), and became their patron. The association with the Pharaoh brought with it the idea that he was the son of Isis, in her original form, who was regarded as a deification of the Queen.

Sun god
Horus represented as a falcon

Since Horus was said to be the sky, he was considered to also contain the sun and moon. It became said that the sun was his right eye and the moon his left, and that they traversed the sky when he, a falcon, flew across it. Thus he became known as Harmerty - Horus of two eyes. Later, the reason that the moon was not as bright as the sun was explained by a tale, known as the contestings of Horus and Set, originating as a metaphor for the conquest of Upper Egypt by Lower Egypt in about 3000 BC. In this tale, it was said that Set, the patron of Upper Egypt, and Horus, the patron of Lower Egypt, had battled for Egypt brutally, with neither side victorious, until eventually the gods sided with Horus (see below).

As Horus was the ultimate victor he became known as Harsiesis, Heru-ur or Har-Wer (ḥr.w wr 'Horus the Great'), but more usually translated as Horus the Elder. In the struggle Set had lost a testicle, explaining why the desert, which Set represented, is infertile. Horus' left eye had also been gouged out, which explained why the moon, which it represented, was so weak compared to the sun.

It was also said that during a new-moon, Horus had become blinded and was titled Mekhenty-er-irty (mḫnty r ỉr.ty 'He who has no eyes'), while when the moon became visible again, he was re-titled Khenty-irty (ḫnty r ỉr.ty 'He who has eyes'). While blind, it was considered that Horus was quite dangerous, sometimes attacking his friends after mistaking them for enemies.

Horus was occasionally shown in art as a naked boy with a finger in his mouth sitting on a lotus with his mother. In the form of a youth, Horus was referred to as Neferhor. This is also spelled Nefer Hor, Nephoros or Nopheros (nfr ḥr.w) meaning 'The Good Horus'. (less info)