Rock art engravings found in Goa exhibit the earliest traces of human life in India. Goa, situated within the Shimoga-Goa Greenstone Belt in the Western Ghats (an area composed of metavolcanics, iron formations and ferruginous quartzite), yields evidence for Acheulean occupation.[Rock art engravings (petroglyphs) are present on laterite platforms and granite boulders in Usgalimal near the west flowing Kushavati river and in Kajur. In Kajur, the rock engravings of animals, tectiforms and other designs in granite have been associated with what is considered to be a megalithic stone circle with a round granite stone in the centre. Petroglyphs, cones, stone-axe, and choppers dating to 10,000 years ago have been found in various locations in Goa, including Kazur, Mauxim, and the Mandovi-Zuari basin. Evidence of Palaeolithic life is visible at Dabolim, Adkon, Shigao, Fatorpa, Arli, Maulinguinim, Diwar, Sanguem, Pilerne, and Aquem-Margaon. Difficulty in carbon dating the laterite rock compounds poses a problem for determining the exact time period.
Early Goan society underwent radical change when Indo-Aryan and Dravidian migrants amalgamated with the aboriginal locals, forming the base of early Goan culture.
In the 3rd century BC, Goa was part of the Maurya Empire, ruled by the Buddhist emperor, Ashoka of Magadha. Buddhist monks laid the foundation of Buddhism in Goa. Between the 2nd century BC and the 6th century AD, Goa was ruled by the Bhojas of Goa. Chutus of Karwar also ruled some parts as feudatories of the Satavahanas of Kolhapur (2nd century BC to the 2nd century AD), Western Kshatrapas (around 150 AD), the Abhiras of Western Maharashtra, Bhojas of the Yadav clans of Gujarat, and the Konkan Mauryas as feudatories of the Kalachuris. The rule later passed to the Chalukyas of Badami, who controlled it between 578 and 753, and later the Rashtrakutas of Malkhed from 753 to 963. From 765 to 1015, the Southern Silharas of Konkanruled Goa as the feudatories of the Chalukyas and the Rashtrakutas. Over the next few centuries, Goa was successively ruled by the Kadambas as the feudatories of the Chalukyas of Kalyani. They patronised Jainism in Goa.
In 1312, Goa came under the governance of the Delhi Sultanate. The kingdom’s grip on the region was weak, and by 1370 it was forced to surrender it to Harihara I of the Vijayanagara empire. The Vijayanagara monarchs held on to the territory until 1469, when it was appropriated by the Bahmani sultans of Gulbarga. After that dynasty crumbled, the area fell into the hands of the Adil Shahis of Bijapur, who established as their auxiliary capital the city known under the Portuguese as Velha Goa (or Old Goa).
In 1510, the Portuguese defeated the ruling Bijapur sultan Yousuf Adil Shah with the help of a local ally, Timayya. They set up a permanent settlement in Velha Goa. This was the beginning of Portuguese rule in Goa that would last for four and a half centuries, until its annexation in 1961.
In 1843 the Portuguese moved the capital to Panaji from Velha Goa. By the mid-18th century, Portuguese Goa had expanded to most of the present-day state limits. Simultaneously the Portuguese lost other possessions in India until their borders stabilised and formed the Estado da Índia Portuguesa or State of Portuguese India, of which Goa was the largest territory.
After India gained independence from the British in 1947, India requested that Portuguese territories on the Indian subcontinent be ceded to India. Portugal refused to negotiate on the sovereignty of its Indian enclaves. On 19 December 1961, the Indian Army invaded with Operation Vijay resulting in the annexation of Goa, and of Daman and Diu islands into the Indian union. Goa, along with Daman and Diu, was organised as a centrally administered union territory of India. On 30 May 1987, the union territory was split, and Goa was made India’s twenty-fifth state, with Daman and Diu remaining a union territory.
Source : Wikipedia