The Centre of Portuguese power in India was Goa.

Goa was the first territory acquired by the Portuguese in India in 1510. It was strategically located on the western coast of India and provided easy access to the spice trade routes. The Portuguese established their headquarters in Goa, which became the centre of their power in India.

Reasons for Portuguese dominance in Goa:

1. Strategic location: Goa was strategically located on the western coast of India, which provided easy access to the spice trade routes.

2. Military strength: The Portuguese had a strong military and naval force, which helped them to establish their dominance in Goa.

3. Diplomatic skills: The Portuguese were skilled diplomats and were able to form alliances with local rulers, which helped them to consolidate their power in Goa.

4. Trade monopoly: The Portuguese established a monopoly over the spice trade in Goa, which helped them to generate huge revenues and strengthen their economic power.

5. Religious conversion: The Portuguese were also successful in converting a large number of locals to Christianity, which helped them to establish their cultural dominance in Goa.

Impact of Portuguese rule in Goa:

1. Urbanization: The Portuguese built several churches, palaces, and other public buildings in Goa, which led to the urbanization of the region.

2. Religious and cultural transformation: The Portuguese introduced Christianity and Western culture in Goa, which led to significant changes in the religious and cultural landscape of the region.

3. Economic development: The Portuguese established a thriving spice trade in Goa, which helped to boost the region's economy.

4. Linguistic influence: The Portuguese language and culture also had a significant impact on the local languages and cultures of Goa.

In conclusion, Goa was the centre of Portuguese power in India due to its strategic location, military strength, diplomatic skills, trade monopoly, and religious conversion. The Portuguese rule in Goa had a significant impact on the region's urbanization, religious and cultural transformation, economic development, and linguistic influence.