Hanuman was born to 'Anjana', a female vanara in the on the Anjaneri hill in the Brahmagiri hills near Traimbakeshwar, Maharashtra. According to the legend, Anjana was an apsara or a celestial being, named 'Punjikasthala', who, due to a curse, was born on the earth as a female vanara. The curse was to be removed upon her giving birth to an incarnation of Lord Shiva. It is also said that Hanuman was born on Anjaneya Hill, in Hampi, Karnataka, near the Risyamukha mountain on the banks of the Pampa, where Sugreeva and Sri Rama met. There is a temple that markets the spot.
Along with Kesari, her husband, Anjana performed intense prayers to Shiva to beget Him as her Child. Pleased with their devotion, Shiva granted them the boon they sought. Hence, the Hanuman is also known as "Maharudra" because he was born out of the boon given to Anjana by the Shiva who is also known as Rudra. The Valmki Ramayana.
(Yuddha Kanda) states that Kesari is the son of Brihaspati and that Kesari also fought on Rama's side in the war against Ravana.
Different stories are told explaining Hanuman's birth. One is that at the time that Anjana was worshipping Lord Shiva, elsewhere, Dasharatha, the king of Ayodhya, was performing the Putrakama Yagna in order to have children. As a result, he received some sacred pudding payasam, to be shared by his three wives leading to the births of Rama, Lakshmana, Bharata and Shatrughna. By divine ordinance, a kite snatched a fragment of that pudding and dropped it while flying over the forest where Anjana was engaged in worship. Vayu, the Hindu deity of the wind, delivered the falling pudding to the outstretched hands of Anjana, who consumed it. Hanuman was born to her as a result.
Being Anjana's son, Hanuman is also called Anjaneya (pronounced Aanjaneya), which literally means "arising from Anjani".
Sri Aurobindo states that "vanara" does not refer to "monkey" "Prajapati manifests as Vishnu Upendra incarnate in the animal or Pashu in whom the fourManus have already manifested themselves, and the first human creature who appears is, in this Kalpa, the Vanara, not the animal Ape but man with the Ape nature", i.e. primitive man such as Homo erectus.
Hanuman, in one interpretation, is also considered as the incarnation of Shiva or reflection of Shiva also known as Rudra. Others, such as followers of Dvaita consider Hanuman to be the son of Vayu or a manifestation of Vayu, the god of wind. When Ravana tried to enter the Kailash (the abode of Shiva) called Lord Shiva 'a monkey" Lord Shiva in return cursed Ravana that a monkey would burn his Lanka Shiva took the form of Hanuman.
Reference to Hanuman in classical literature could be found as early as those of 5th to 1st century BC in Panini's Astadhyayi, Abhiseka Nataka, Pratima Nataka, and Raghuvamsa (Kalidasa).