Modern day Hinduism is derived from the Vedic religion of the Aryans. Many of the deities are still worshipped by Hindus in one form or another. The Vedic religion also has connections with Zoroastrianism, Iranian paganism, and even Greek and Norse mythology, if you know where to look.
Almost all the Indo-European religions are based around the sky father and earth mother, as well as a powerful storm god-king. Uranus and Gaea are the prime example in Greek mythology, as well as their grandson Zeus, the god of thunder and the king of the gods. Zeus is the equivalent of Jupiter (Jove Pater) in Roman mythology and is also connected to Odin and Thor in Norse Mythology. In Aryan mythology, Dyaus Pitr (the god of the daylight sky) is the oldest Vedic god praised in the Rigveda who is similar to Uranus. Dyeus Pitr and Prithvi Mata (the earth goddess) are separated by the storm god Indra, who takes his place as the king of heaven. Indra, like Thor and Zeus has a thunderbolt for his weapon, as well as the rainbow (Indradanush, which is actually supposed to be quite scary), as well as the first sword Asi.
Indra is the eldest of the 12 Adityas, who are all somehow connected to the sky, sun, and order. In order the Adityas are: Indra (the king of heaven), Aryaman (the protector of the Aryans), Tvasthr (the smith, who has a counterpart in Iranian paganism and the father of Yama), Varuna (the god of oceans, dusk, and order), Bhaga (the god of wealth, similar to Pluto), Dhatri (a solar deity), Surya (THE solar deity), Vivaswan (another sun deity), Agni (the fire god), Mitra (the god of mornings, order, and another solar deity; like Varuna), Amsha (another solar deity), Pushan (the god of meetings, Parjanya (the god of clouds), and Vishnu/Vamana (a dwarf, as well as the youngest and de facto leader of the Adityas, later combined with Krishna and Narayana to become chief god of Vaishnava sect).
Here, Indra, Mitra, and Agni are the most important gods. Mitra is also found in Iranian paganism and Zoroastraniasm along with Agni (Dashtagni/Atar in Avestan), and also had a cult in Imperial Rome (which was just taken from the Persians) that made him out to be some kind of Hercules-like hero, which he originally had no association with. Chandra the moon god is also a main figure in the Rigveda. He is known as Soma, for the fermented punch that he drinks called soma, or amrita (against death) which makes one immortal. The concept of soma or ‘haoma’ is also found in Zoroastrianism and Iranian religion as a drink that induces hallucinations.
These are just some of the similarities in Indo-European mythologies, and today we just uncovered the tip of the iceberg. There are a lot more connections to unravel and we can go even further.
Anay Ganesh 