Introduction:
The Vedas are the oldest sacred texts of Hinduism and are considered to be the foundation of Indian philosophy, spirituality, and culture. They are believed to have been orally transmitted from generation to generation for thousands of years before being written down. The Vedas are divided into four main texts: Rigveda, Samaveda, Yajurveda, and Atharvaveda. Among these, the Rigveda is considered to be the oldest Veda.

Explanation:
Rigveda:
The Rigveda is the oldest and most important of the four Vedas. It is believed to have been composed between 1500 BCE and 1200 BCE, making it over 3,500 years old. The Rigveda is a collection of hymns, prayers, and rituals dedicated to various deities. It consists of 1,028 hymns divided into ten books called Mandalas. The hymns are written in Sanskrit and contain important insights into the religious beliefs, rituals, and social structure of the ancient Indus Valley civilization.

Samaveda:
The Samaveda is the second oldest Veda and is closely related to the Rigveda. It is believed to have been compiled around the same time as the Rigveda, but its hymns are taken from the Rigveda and set to music. The Samaveda focuses on the musical aspect of the hymns and is considered to be the earliest known musical text in the world.

Yajurveda:
The Yajurveda is the third oldest Veda and is primarily a collection of verses and prose formulas used in rituals. It is believed to have been composed between 1200 BCE and 900 BCE. The Yajurveda provides instructions for performing rituals and sacrifices and includes explanations of their significance.

Atharvaveda:
The Atharvaveda is the youngest of the four Vedas and is believed to have been composed between 900 BCE and 600 BCE. It contains hymns, spells, and incantations used for various purposes, including healing, protection, and prosperity. The Atharvaveda is considered to be more diverse in content and covers a wider range of topics compared to the other Vedas.

Conclusion:
To summarize, the Rigveda is the oldest of the four Vedas and is estimated to be over 3,500 years old. It is followed by the Samaveda, Yajurveda, and Atharvaveda in terms of age. The Vedas are not just religious texts but also serve as valuable historical and cultural records of ancient India.