Complex sentence: Pre-sectarian Buddhism may refer to the earliest Buddhism, the ideas and practices of the Buddha himself, but also to early Buddhism as existing until about one hundred years after the Parinirvana of the Buddha, until the first documented split in the Sangha.
Split into simpler sentences: Pre-sectarian Buddhism may refer to the earliest Buddhism, the ideas and practices of the Buddha himself. It may also refer to early Buddhism as existing until about one hundred years after the Parinirvana of the Buddha, until the first documented split in the Sangha.