Vasco da Gama discovered the sea route from Europe to India by sailing around Africa, bypassing Arab intermediaries. He landed at Calicut (Kozhikode) with the help of a Gujarati pilot. His arrogance angered the Zamorin (ruler of Calicut) and local Muslim traders, pushing him toward alliances with their rivals in Cochin and Cannanore. The Portuguese later defeated an Egyptian Mamluk fleet at Chaul, near Mumbai in 1508, weakening Arab dominance over the Indian–Arab trade. Da Gama eventually became Portuguese viceroy after Goa was conquered. He thought Hindus were debased Christians and, like many of his contemporaries, carried deep hostility toward Muslims. His fleet even burnt pilgrims aboard a ship returning from Mecca. The Wikimedia image of a painting in National Library of Portugal shows Vasco da Gama before the King of Portugal.

The Bijapur Sultanate had seized Goa from Vijayanagara and had sharply increased land revenue. Discontented Hindu leaders, including Timoja, invited Afonso de Albuquerque to intervene, expecting him to leave after receiving tribute. Instead, Albuquerque captured Goa from Yusuf Adil Shah in 1510 and expelled or killed the resident Muslim population. By 1560, the Portuguese held Old Goa, Bardez, Salcete, Daman, and Diu. They later acquired areas such as Ponda and Bicholim in the 18th century. Their influence also extended to Vasai near Mumbai (1535–1739) and to protectorates such as Cochin until the Dutch captured it in 1663. Portuguese traders were active on the east coast at San Thome (Chennai) and Hooghly, from where Shah Jahan expelled them in 1632. The Wikimedia image of a wall painting in Lisbon shows Albuquerque attacking Malacca.

The Spanish established the inquisition in 1481 to ensure that Jewish converts remained within the Church. Portugal followed in 1541. At the insistence of The clergy, the Goa inquisition was established in 1560, initially targeting recent converts but later expanding to anyone accused of offending Church doctrine. Proceedings were secret, testimonies coerced, and punishments severe—including torture —to deter others. Many people, including Europeans, used the institution to settle personal scores. During the annual *Auto -de-Fé*, convicts were publicly paraded and some were burnt. Very few accounts or buildings of the Goa inquisition survive. However, historians indicate that it was more severe than in Europe. It handled 16172 cases before it was abolished in 1820. Some claim that the hath-katro pillar (where hands of convicts were cut) in Old Goa is from the inquisition. Not all are convinced. The image from storytrails.com shows a procession of condemned people during Goa Inquisition.

Francis Xavier is one of the most famous missionaries in the history of church. He evangelised in India, Malaya & Japan. He arrived in India in 1542 and died in 1552. his embalmed body was brought to the Basilica of Bom Jesus in Goa the following year. In 1683, during a major Maratha attack, the Portuguese viceroy placed his sceptre before Xavier’s casket as a last appeal for divine intervention. Coincidentally, the Mughals attacked the Marathas from the rear, forcing them to retreat. Xavier was thereafter venerated as “Goencho Saheb.”
Today, many educational institutes in India bear his name but St. Xavier has a controversial side too. In a letter to the king of Portugal dated May 16, 1545, he specifically asked for the establishment of the Inquisition, the medieval institution of terror for heretics in Catholic territories. The Wikimedia shows a Japanese depiction of St Xavier.

The Syrian Orthodox community (St Thomas Christians) in Malabar were flourishing when the Portuguese landed. Initially, they were allies. The community traced their lineage to St Thomas, disciple of Jesus, who is claimed to have travelled to India and martyred in 52CE. The Portuguese discovered the tomb of St Thomas in 1517 at Meliapur in Chennai, later renamed San Thome. The Syrian Orthodox community followed the Syriac or Nestorian Church with a different Bible called Peshitta (simple). The Portuguese viewed this as heresy.
After the Synod of Diamper in 1599 (religious council), they forced the community to adopt Latin rites. Syrian Christian books were burnt; legends suggest only one copy of the Syriac Bible was saved. In 1653, a section of Syrian Christians took the Coonan Cross Oath to preserve their ancient rites. The community then split into Rome affiliated Syro Malabar Church and the independent Jacobite Syrians, largely the Syrian Malankara Church. The image is of a Syriac Bible donated by the Malankara Church to Dr Buchanan in 1806, preserved at Cambridge Univ.

Devi Bhagawati was brought to Marcel in 1673 to escape deity breaking. The annual yatra to Tiswadi remembers this event.
Hindus had helped Portuguese take Goa. Initially they were treated well. Legal discrimination started in 1540 and officially ended only in 1910. However it had eased from 18th century onwards.
Pearson notes that from 1540 onwards, all temples were destroyed to encourage conversion, in Old Goa, Bardes and then in Salcette. Most Hindu ceremonies were forbidden, including marriage and cremation. Distraught brahmins saved the deities and took them just outside Portuguese territory. This is why several great temples are in the Ponda area. It was acquired by the Portuguese only in the more tolerant 18th century.
The Viceroy Joao Saldanha said in 1729 that the ruin of Goa (then) was due to lack of commerce, since the merchants, Hindu & Muslim, viewed the Holy office with horror. The image from the temple’s website is of the Shri Bhagawati Haldonkarin Devasthan at Marcel, Goa.

In 1683, Sambhaji’s forces reached the gates of Old Goa, which seemed on the verge of falling. But a simultaneous Mughal attack on the Maratha rear forced him to withdraw. Later, in 1739, Chimanji Appa expelled the Portuguese from the Mumbai region after an intense two-year campaign, culminating in the capture of Vasai. Chimanji allowed the defeated Portuguese to leave with honour.
The Portuguese had converted the ancient Mandapeshwar temple in Mumbai into a church and renamed it as Mount Poinsar. Marathas turned it back into a Shiva temple. British later built a church next door. This is the popular IC Church in Dahisar/Poinsar.
The Marathas confiscated many huge & melodious church bells and offered them to Hindu temples. They can still be seen. The Reddit image shows Portuguese bells at the famous Bhimashankar temple.

The Portuguese had captured the seven islands of Mumbai from the Sultan of Gujarat in 1535. When Charles II of England married Catherine of Braganza in 1662, these islands—then called “Bom Bahia” (Good Bay)—were transferred as part of her dowry to the English. The Portuguese retained adjacent territories such as Vasai until their defeat by the Marathas in 1739. The British took these over from Marathas in 1780. Many Portuguese era Mumbai churches like St Michael’s at Mahim & Mount Mary in Bandra are still popular.
The image from the Royal Collection Trust shows the old English fort at Bombay.

The Portuguese tried to control spice trade in the east. They imported Arab horses with the money from spice trade. These were coveted by the kings in India.
In the 16th cent CE, Portuguese were friendlier to the Hindu Vijayanagara Empire compared to the Deccan Sultanates. So they delivered the horses to Vijayanagara, but asked the Sultanates to take them from Goa. Some of the best accounts of the Vijayanagara Empire are by Portuguese horse merchants like Domingo Paes.
This trade declined after the fall of Vijayanagara in 1565. The clergy also exerted pressure not to sell horses to infidels. By the 18th cent, the Portuguese had lost their monopoly both in spices and horses. Their glory days in India were behind them and Goa declined. The Wikimedia image by Sarah Welch is of the base of Vitthala temple at Hampi showing foreign merchants bringing horses to Vijayanagara.

Potatoes originated in South America and entered India through the Portuguese in the early 17th century. They also introduced tobacco, pineapple, papaya, maize, sweet potatoes, cashews, and red peppers. Their grafting techniques produced new mango varieties, including the famous Alphonso.
Garcia de Orta, a famous physician, wrote a landmark book (published 1561) on the medicinal properties of Indian plants & minerals and native diseases. Unfortunately, his Jewish convert family was a victim of the Goa Inquisition. His sister was burnt to death. Orta’s body was exhumed and burnt. Orta is now hailed as a hero in Portugal. The image from storytrails.com is that of his statue in Lisbon.

The Jesuits introduced Asia’s first printing press in Goa in 1556, the fourth outside Europe. The press did not provide scientific impetus. Out of forty books printed from 1556 to 1679, 37 were religious books. As their religious zeal increased and their trade influence decreased, merchants fled and Goa went into a decline. The Jesuits’ press closed down in 1683. Goa had no printing facility again until 1821.
Portugal itself was late to the industrial revolution. Goa was thus much poorer than British India. This made many Goans migrate to Mumbai & other cities in the early 1900s. Portuguese dictator Salazar started mining projects in Goa during his rule (1932 onwards) but did not stop the decline.
The image by Serendipity Arts is the remnant of St Paul’s college in Goa where the first printing press was housed.

‘Casta’ in Portuguese means ‘lineage’. It was used to describe race categories based on ‘purity’ of blood. Pearson writes, “…the familiar Iberian gradation, starting with those born in Portugal (reinoes) and descending through those born in Asia of Portuguese parents (castigos or Indiatkos) to those born in Asia of Portuguese and Indian, or Portuguese and African, parentage (respectively mestigos and mulattoes).” He also says “Outside this ranking, and beneath it, were the native Christians, but even the castigos and the mestigos were regarded with considerable suspicion by the elite.”
The Hindu system of jati-varna was already existing and old by the time the Portuguese arrived. So it is difficult to understand why the term caste started getting used for it. The Wikimedia image is of a painting in Mexico depicting 16 racial categories in the casta system.