Although the origins of Mahayana are not completely understood, scholars believe that it originated in India in the 1st century BCE or the 1st century CE.
It is not uncommon for Mahayana Buddhists to trace the origins of the Mahayana back to Gautama Buddha. The Heart Sutra and the other Prajnaparamita sutras are considered the word of the Buddha, either being actually spoken by Shakyamuni or the speaker being directly empowered by him (as is the case with the Heart Sutra). Thus, the prologues of the sutra reports that it was set forth by the Buddha on Vulture Peak in what is said to be the second turning of the wheel of the Dharma, reinterpreting and superseding that delivered at the deer park in Sarnath.
Because no mention was made of these sutras in the early councils in which the teachings of the Buddha were compiled, the proponents of the new Mahayana claimed that the new sutras had been taught by the Buddha to a select group of disciples, their content being, at that time, inappropriate to a general audience. The sutras were then placed into the hands of various deities and nagas for safekeeping until the world was ready for their teaching.
Although the history of the many different schools of Buddhism at this time is poorly understood, we can closely link the arising of the Mahayana school of Buddhism with the writing of the new Mahayana Sutras (including, first and foremost, the Prajnaparamita sutras).