The Mahāparinirvāṇa Sūtra most commonly refers to an ancient text written originally in Pali that recounts the Buddha’s final months on earth, the last sermons of the Buddha, the death of the Buddha, and the Buddha’s cremation. Both known by the same title, the name Mahāparinirvāṇa Sūtra can actually refer to two different texts. The first of these is the collection of original Pali texts, the Mahāparinibbāṇa Sutta, which is found in the Dīgha Nikāya known in English as The Long Discourses of the Buddha.  The second of these is the Mahayana text that is a reformulation of the Pali text, with additional ideas added. The Mahayana Mahāparinirvāṇa Sūtra is known in the English-speaking parts of the world as the Nirvāṇa Sūtra.
The Mahāparinibbāṇa Sutta, which is the canonical account of the Buddha’s final times, his death, and the events thereafter, is traditionally said the be the documentation of the events after the Buddha’s death by his disciples. This is contested by scholars on the subject who say that, though the disciples may have met after his death, it is nearly impossible that the discussion held at the time is related to the text found in the sutta, and the events were likely told through oral tradition for years before they were written down in Pali. The Mahāparinibbāṇa Sutta is not, however, the earliest account of the Buddha’s death, which is most likely found in the Vinaya, the canonical rules of Buddhism, of which the Mahāparinibbāṇa Sutta reiterates much of its account. The Mahāparinibbāṇa Sutta, the sixteenth sutta of the collection, is the longest of the thirty-four suttas found in The Long Discourses of the Buddha. The Mahayana text, for which the spelling Mahāparinirvāṇa Sūtra is commonly used, is a different text entirely from the shorter Mahāparinibbāna Sutta on which the sūtra was initially based. It was written initially in Sanskrit and was then translated multiple times into Chinese and Tibetan, each of which contain multiple disparities, with four very different surviving translations: the 418 CE Chinese six-fascicle version, the 422 CE Tibetan 40-fascicle translation, and the 424-453 CE 36-fascile Chinese edition. Though the Mahayana Mahaparinirvāṇa Sūtra has undergone changes and additions throughout each translation, the longest and earliest of these translations begins with an account of the Buddha’s death after which thousands of monks and Mallas are beckoned to come to the spot in Kushinagara where the Buddha has attained Parinirvāṇa.  The Mahayana account of the death of the Buddha differs most noticeably in the perspective from which the story is told, the Pali text focusing far more on the actions and words of the Buddha, and the Mahayana text centering on the actions and words of his followers. The rest of the sūtra, which is nearly 400 pages longer in the English translation than the Mahāparinibbāṇa Sutta, includes chapters of definitive Mahayana principles, many of which are unrelated to the death of the Buddha, but all of which have become very instrumental in the development of Mahayana Buddhism in China.