The Rig Veda is one of the oldest sacred texts of Hinduism, composed around 1500 BCE. It is a collection of hymns dedicated to various deities, such as Indra, the god of thunder, and Agni, the fire god. These hymns are written in Sanskrit and reflect the spiritual and philosophical ideas of ancient Indian society. The Rig Veda consists of ten books, known as Mandalas, containing over a thousand hymns. It serves as a crucial source for understanding early Vedic culture, rituals, and beliefs. The text emphasizes the importance of sacrifice and the relationship between humans and the divine, shaping the foundation of later Hindu thought.