The epic is told by Vyasa, who is one of the major dynastic characters within the epic. The first section of the Mahabharata states that it was Lord Ganesh (the elephant-headed god of the Hindus) who, at the behest of Vyasa, wrote the epic down on manuscript. Lord Ganesh is said to have agreed, but only on condition that Vyasa never pause in his recitation. Vyasa then put a counter-condition that Ganesh understand whatever he recited, before writing it down. In this way Vyasa could get some respite from continuously speaking by saying a verse which was difficult to understand. This situation also serves as a popular variation on the stories of how Ganesh's right tusk was broken (a traditional part of Ganesh imagery). This version attributes it to the fact that, in the rush of writing, the great elephant-headed divinity's pen failed, and he snapped off his tusk as a replacement in order that the transcription not be interrupted.
The Mahabharata is thought to have been derived from what was originally a much shorter work, called Jaya (Sanskrit for Victory). The dating of the events of this story is unclear. Very few people find the events to be reliably placed in Vedic India around 1400 BC. Scholars have studied the astronomical activities described in the Mahabharata (like eclipses) and have claimed to have dated it to around 1478 BC or alternatively 3106 BC. However, it is significant to realize that the debate about dating the 'events' of the Mahabharata is secondary to the importance of the text in Classical Sanskrit literature and culture.
Like much of other early Indian literature, it was often transmitted by oral means through the generations. This made it easier for additional episodes and stories to be interpolated within it. It also resulted in regional variations developing. However, the variation has in most cases been in the new additions, and not in the original story.