Short answers, pulled from the story.
The official name is the Democratic Socialist Republic of Sri Lanka, a title that was formalised on the 7th of September 1978. Before that, the country was known as Ceylon under British rule and was previously the Free, Sovereign and Independent Republic of Sri Lanka from 1972.
Serendipity derives from Sarandīb, the name Arab and Persian travellers used for Sri Lanka, which itself came from the Sanskrit word Siṃhaladvīpaḥ. European writers adapted the island's name into the word for a happy, unexpected discovery.
The civil war began in 1983 and ended on the 19th of May 2009, when the Sri Lanka Armed Forces defeated the Liberation Tigers of Tamil Eelam (LTTE) under the Presidency of Mahinda Rajapaksa. The 26-year conflict killed between 60,000 and 100,000 people.
The collapse resulted from a combination of rapidly increasing foreign debt, large government budget deficits caused by tax cuts, falling foreign remittances, a food crisis linked to a nationwide ban on inorganic fertilisers, and a sharp decline in tourism. Sri Lanka defaulted on its $51 billion sovereign debt for the first time in its history, and Prime Minister Ranil Wickremesinghe declared the economy had collapsed in a June 2022 address to parliament.
Buddhism was introduced to Sri Lanka in 250 BCE by Mahinda, a bhikkhu and son of the Mauryan Emperor Ashoka, who arrived at Mihintale during the reign of King Devanampiya Tissa. In 245 BCE, bhikkhunī Sanghamitta arrived with a sapling of the Bodhi Tree, considered the oldest continuously documented human-planted tree in the world.
The Jaya Sri Maha Bodhi is a tree brought to Sri Lanka in 245 BCE by bhikkhunī Sanghamitta, regarded as a sapling from the Bodhi Tree under which Gautama Buddha became enlightened. It is considered the oldest human-planted tree with a continuous historical record in the world.