It had been the most mundane of mornings in May 1985 when gunmen opened fire on a bus stop in Anuradhapura, Sri Lanka, spraying bullets into waiting commuters. On their way out of town, the militants stopped to slaughter again—this time at a temple where legend says the giant Bodhi tree (Ficus religiosa) had been planted centuries ago as a shoot from the tree under which the Buddha achieved enlightenment.

“They killed even an old lady selling flowers,” a temple guide told me, still in shock. “They shot at beggars.” As many as 180 people died that day, including staffers at a nature reserve along the attackers’ escape route. It was my first reporting experience in Sri Lanka.

These were not the first and obviously not the last deaths of innocents on a horrific scale, as the Easter Sunday tragedy in Colombo reminds us. This island nation of just over 21 million people has the highest levels of human development in South Asia yet has endured decades of suffering. Thousands have been killed amid contentious politics, ethnic grudges, sectarian violence, and a caste system, an affliction that persists across much of South Asia.

Since Sri Lankan independence in 1948, assassinations have decimated the political leadership, and journalists and public intellectuals have disappeared or been murdered. Victims’ bodies have clogged rivers or been tossed into the sea. As if that were not enough, more than 35,000 Sri Lankans were swept away in the 2004 tsunami that raced across the Indian Ocean after an earthquake off the Indonesian island of Sumatra.

What is new about the Easter tragedy is that Islamic terrorism, homegrown or imported, has apparently emerged from the Muslim minority in Sri Lanka, a country dominated by the Sinhalese Buddhist majority and a substantial Hindu Tamil population. There are Christians on both sides of the Sinhala-Tamil divide. Civil conflicts have never before been solely religious or racial.

The shock of Islamic terrorism will resonate across South Asia, nowhere more than in India, where a Hindu-nationalist government under Prime Minister Narendra Modi is in the middle of elections. Surveys show that India’s 200 million Muslims have been held back educationally, economically, and socially. In recent years Hindu extremists have murdered Muslims on false claims that they were harming cattle, a sacred icon for Hindus, and other offenses. Kashmiri Muslims, who are seeking independence from or significant autonomy within India, are living under martial law. In Sri Lanka, the attacks could open religious fissures where none existed, and in India, Hindu nationalists could use them as an excuse to further divide and oppress.

Sri Lanka, today arguably the most diverse country in South Asia, was ruled by native kings when Arabs from across the Indian Ocean established footholds for trade in spices more than 1,000 years ago. They named the island Serendip, from which the English word “serendipity” derives. Some settled and were the forerunners of today’s Muslim minority. The Portuguese arrived at the start of the 16th century, bringing Roman Catholicism, with its exquisite Iberian-inspired churches. The island got another new name: Ceylon, from the Portuguese Ceilão. Then came the Dutch in the 17th century. They brought strict Protestantism and built sturdy churches, houses, and administrative buildings. A new ethnic designation, Burgher, entered the mix and is still claimed by people of European descent.

In 1833, after the British defeated the last of the indigenous kingdoms, the island became a full-fledged colony, separate from British India. Without any fighting, Britain granted it independence in 1948, and 24 years later, it got another new name: Sri Lanka.

The descent into a poisonous linguistic/ethnic hatred and civil warfare began in 1956, when Prime Minister Solomon W.R.D. Bandaranaike (an Oxford University graduate) of the Sri Lanka Freedom Party succumbed to pressure from the majority Sinhalese population and declared Sinhala the country’s only official language.

Three years later, violence against Tamils, whom the Buddhist Sinhalese claimed were getting too many government jobs, claimed more than 200 lives. Many Tamil civil servants, Hindus, and Christians had been educated in English by the British and in American missionary schools in Jaffna, the Sri Lankan Tamil homeland and center of Tamil culture. They spoke Tamil and English, rarely Sinhala as a first language. (Other Tamil speakers not connected to Jaffna were brought in as laborers to the tea plantations in the island’s central hills; they are called Indian Tamils.)

Less than a decade later, the Liberation Tigers of Tamil Eelam, a separatist movement, took shape in Jaffna, with support and safe houses in the Indian state of Tamil Nadu. Under Velupillai Prabhakaran, a ruthless warlord, the Tigers soon eliminated the more moderate Tamil leaders to create a rebel-controlled area in the north and east of the island.

Those of us who visited Prabhakaran’s domain saw a virtual open-air prison under a regime that enforced mindless obedience, including a vow of suicide to avoid detention, and total militarization. Jaffna University scholars were targeted for harassment and sometimes death. Years later, the LTTE killed Sri Lanka’s leading human-rights lawyer, Neelan Tiruchelvam, as he was being driven to his office in Colombo. He was a Tamil who had devoted his life to studying ethnic conflict and had tried to build bridges among Sri Lankan communities and cultures.

Open civil war between north and south began on a large scale in July 1983 after 13 Sri Lankan soldiers were gunned down in an ambush near Jaffna and President J.R. Jayewardene allowed their bodies to be taken to Colombo for last rites, setting off cataclysmic rage among the Sinhalese. Estimates of Tamil deaths in Buddhist-controlled areas around this time range from the mid-hundreds to several thousand.

This critical failure of Buddhist leadership presaged other missteps. It is telling that the current government or at least its security forces were warned several times by foreign intelligence agencies about attacks being planned for this Easter Sunday but did not act in time.

Over the years, the alienation and abuse of Tamils drove many into a potent diaspora. Jaffna Tamils became prominent in law and politics in Singapore and Malaysia. There and in the West, they were effective fund-raisers, often through extortion, and propagandists for the LTTE. The inward-looking Sri Lankan government could never compete on the international stage.

As the war between the government and Tamil rebels continued, a violent leftist Sinhalese movement, the Janatha Vimukthi Peramuna (People’s Liberation Front), was resurrected among students and other disaffected youths. It was given added strength when India and the Jayewardene government reached an agreement to send 45,000 Indian peacekeeping troops to the Jaffna area in 1987. It proved a fatal mistake; the LTTE turned its wrath on the Indians, killing more than a thousand of them before the force was withdrawn in 1990.

The LTTE sustained the war until its bloody, humiliating defeat by Sri Lankan government forces in 2009, with horrific human-rights abuses on both sides. President Mahinda Rajapaksa crowed and showed not a shred of sympathy or expression of humanity for the tens of thousands of lives lost over more than three decades. There were instead calls to raise Buddhist flags over Jaffna.

Before the war ended, there was one more death, a historic one. Rajiv Gandhi, a former prime minister of India, was in Tamil Nadu in May 1991, hoping to return to office. He had regretted the role his mother, Indira Gandhi, played in covert and sometimes overt support for Sri Lanka’s rebels. They, in return, had not forgotten his decision to send Indian troops to Jaffna to disarm and humiliate them.

Near the end of a long day on the campaign trail, a young woman bearing a garland knelt to touch Rajiv Gandhi’s feet. As she bent, she ignited a suicide vest, blowing him to pieces. She was a Tamil sent on this errand by the LTTE, whose leader had never forgiven him. India’s venerable Congress Party has not been the same since.

Sri Lanka has long an irritant to India for its pro-Western and, more recently, pro-Chinese policies. It is hard to imagine India standing aside if Muslims appear to be bringing Islamic radicalism into the region. After the Easter massacre, Tisaranee Gunasekara, a Sri Lanka journalist and political analyst, noted in Himal Southasian, an online journal, that Sri Lankan Muslims, while at times the victims of violence, had never employed retaliatory attacks until they felt the sting of Islamophobia.

The attack by Muslims on Christian churches in the name of religion, Gunasekara wrote, opened another, new divide in Sri Lankan society. “The Easter Sunday massacre marks a turning point because it is the first religion-inspired suicide bombing in Sri Lanka,” she wrote. “And in a cruel irony, it involved the country’s two most politically peaceful communities, thereby creating a faultline where none existed.”