The influence of Zoroastrianism on Vedic thought can be traced back to the early Vedic period, around 1500 BCE. Both Zoroastrianism and Vedic thought share common roots in the Indo-Iranian culture and language, and over time, their ideas and beliefs have evolved and influenced each other.

One of the main areas of influence is the concept of duality or dualism. Zoroastrianism introduced the idea of a cosmic battle between good and evil, represented by the god Ahura Mazda and the demon Angra Mainyu. This concept was later adopted by Vedic thought, where it is known as the struggle between the Devas (gods) and Asuras (demons). This duality is also reflected in the Vedic concept of Purusha and Prakriti, representing the male and female energies of the universe.

Another significant influence of Zoroastrianism on Vedic thought is the concept of monotheism. While Vedic thought initially revolved around the worship of multiple deities, Zoroastrianism introduced the idea of a single, all-powerful god. This concept evolved in Vedic thought to the worship of one supreme god, known as Brahman, who is seen as the creator and sustainer of the universe.

The influence of Zoroastrianism can also be seen in the Vedic concept of karma and reincarnation. Zoroastrianism introduced the idea of individual judgment and accountability for one's actions in the afterlife, which is reflected in the Vedic belief in karma and rebirth. Both religions believe in the cycle of birth, death, and rebirth, with the ultimate goal of achieving liberation from this cycle through spiritual enlightenment.

Over time, as Zoroastrianism and Vedic thought interacted and influenced each other, we see a blending of ideas and beliefs. For example, the Vedic god Indra, who was initially seen as a warrior god, evolved to become a protector of righteousness, similar to the Zoroastrian god Ahura Mazda. Similarly, the Vedic concept of fire worship, known as Agni, was influenced by Zoroastrianism's emphasis on fire as a symbol of purity and divinity.

In conclusion, the influence of Zoroastrianism on Vedic thought has evolved over time, with the two religions sharing common roots and ideas. This exchange of beliefs has enriched both religions, leading to a deeper understanding of the universe and our place in it. It is a testament to the power of cultural exchange and the continuous evolution of human thought.