For thousands of years, people all over the world have believed in the influence of the planets on human life and history. Logically speaking, the creation of the grahas or planets precedes that of the living beings. Hence, some sort of cause and effect relation must subsist between these two. This seems to be the basis for this belief.
The Navagrahas or the nine planets are regarded by the Hindus as of the greatest astrological significance and are believed to influence the life of the individual as also the course of history.
As per the traditional list, the nine planets are: Ravi or Sūrya (Sun), Soma or Candra (moon), Maṅgala or Kuja or Aṅgāraka (Mars), Budha (Mercury), Bṛhaspati or Guru (Jupiter), Śukra (Venus), Śani (Saturn), Rāhu and Ketu.
The seven days of the week have derived their names from the first seven planets. Rāhu and Ketu are not planets but ascending and descending nodes of the moon.
Budha or Mercury is the fourth in this group of nine planets. According to Hindu mythology, he is the son of Candra and Tārā. He had once been transformed into a woman when he entered the forbidden forest area, the Kumāra-vana. Hence he is also considered as a strīgraha, a feminine planet. He is saumya (pacific in nature) and śubha (auspicious). In images he is shown either as dark or yellow in complexion, wearing a garland of yellow flowers, with four arms, carrying in his hands sword, shield and mace, the last one being in the varadamudrā (gesture of bestowal of boons). His consort is Iḷā.