As per the legend, during the Pandavas' exile which was inflicted by their cousin Duryodhana, Bhima became arrogant. Hence, in order to control Bhima's arrogance, Hanuman considered himself as the brother of Bhima. Hanuman appeared in the forest in the form of weak and aged monkey. While in search of a fragment flower, Bhima saw Hanuman lying on the floor with his tail blocking the way. Bhima was not aware of the Hunuman's identity and contemptuously asked him to remove the tail. However, Hanuman demonstrated himself as weak and old and incapable of removing the tail of his own. In such circumstances, Bhima tried to remove the tail but despite several efforts failed to do so. Bhima, came to know that the monkey was his own brother ands thus apologized for his arrogant behavior. Hanuman showed his real form and enlarged himself and showed Bhima the size with which he crossed the sea in order to look for Sita during the Ramayana period. After winning over the Kurukshetra war against the Kauravas, Pandavas started staying in Indraprastha and developed five temples of Hanuman.
As per the legend, it is said that the writer of Ramayana, Tulsidas visited this temple in Delhi. During his visit, he was called by Mughal Emperor and was asked to perform some miracles. Tulsidas was capable of doing so with the blessing of Lord Hanuman. Being pleased with him, the Emperor presented him with a Hanuman temple consisting of Islamic crescent moon. It is often believed that because of the moon over the temple spire, the temple was not destroyed by the Muslims who attacked India numerous times.
It is also said that the temple was originally constructed by King Man Singh I of Amber during the period of Akbar's rule. The temple was reconstructed by Maharaja Jai Singh in the year 1724 when Jantar Mantar was build. One of the salient features of this temple is the 24 hours chanting of the mantra that says 'Sri Ram, Jai Ram, Jai Jai Ram'.
One can get into the temple through Baba Kharak Singh Road. You can see numerous marble steps that shall lead you towards the main entrance of the temple. There are massive silver doors that have been engraved with scenes of Ramayana story. The hall tends to posses clerestory windows that has been decorated by paintings of Hanuman. Below the paintings, one can see Sundar Kand carved over the marble tablets fixed upon the walls. The Hanuman idol has been placed on the north wall and on the right side of the hall. The idol tends to face the southern direction. You can see images of Radha and Krishna, Rama, Lakshmana as well as Sita have been installed in the right side of the Hanuman idol.